* Please note that most treatment modalities listed below are based on conventional medicine. PreventDisease.com does not advocate the use of any pharmaceutical drug treatments. Long-term drug therapy is very detrimental to human health. All drug information is for your reference only and readers are strongly encouraged to research healthier alternatives to any drug therapies listed.
rectal cancers (often referred to collectively as colorectal
cancer) are malignancies (life-threatening tumors) that develop
in the large intestine. [ See Box The Gastrointestinal
Tract.] Most tumors evolve from adenomatous polyp s
(small benign gland-like growths) that develop on the mucous
membrane, which lines the large intestine. They are usually
one of the following types:
WHAT ARE COLON AND RECTAL CANCERS?
polyps (over an inch) are more dangerous than smaller ones.
Progression to cancer takes about five to ten years in most
cases, except for certain inherited forms, which develop more
Tubular polyps, which protrude mushroom-like, or
Villous adenomas, which are flat and spreading and are
more apt to become malignant.
THE GASTROINTESTINAL TRACT
gastrointestinal (GI) tract (the digestive system) is
a tube that extends from the mouth to the anus. It is
a complex organ system that first carries food from
the mouth down the esophagus to the stomach and then
through the small and large intestine to be excreted
out through the rectum and anus.
esophagus, commonly called the food pipe, is
a narrow muscular tube, about nine and a half inches
long, that begins below the tongue and ends at the stomach.
the stomach, acids and stomach motion break food
down into particles small enough so that nutrients can
be absorbed by the small intestine.
small intestine, despite its name, is the longest part
of the gastrointestinal tract and is about 20 feet long.
Food that passes from the stomach into the small intestine
first passes through three parts:
of the digestive process occurs in the small intestine.
First it enters the duodenum,
Then the jejunum, and
Finally the ileum.
material, such as plant fiber, is passed to the large
intestine , mostly in liquid form. The large intestine
is approximately six feet long and is the final portion
of the digestive tract. It follows the small intestine
and includes the cecum, the appendix,
the colon, and the rectum, which extends
to the anus.
Cecum and Appendix. The cecum and the
appendix are located in the lower-right quadrant
of the abdomen.
Colon. The colon absorbs excess water and salts
into the blood. The remaining waste matter is converted
to feces through bacterial action. The colon is divided
into four major sections.
and Anus. F eces are stored in the descending and
sigmoid colon until they are passed through the rectum
and anus. The rectum extends through the pelvis
from the end of the sigmoid colon to the anus.
The first section, the ascending colon ,
extends upward from the cecum on the right side
of the abdomen.
The second section, the transverse colon ,
crosses the upper abdomen to the left side.
The third section extends downward on the left side
of the abdomen toward the pelvis and is called the
descending colon .
The final section is the sigmoid colon .
WHAT CAUSES COLON AND RECTAL CANCERS?
defects in genes that normally protect against cancer play
the major role in causing polyp cells to proliferate unceasingly
and become cancerous. Most of these defects however are acquired
in an individual patient, and are not inherited. In some cases
of hereditary colon cancer, the responsible genetic abnormalities
have not yet been identified.
APC Gene. When the adenomatous polyposis coli (APC)
gene is normal, it helps suppress tumor growth. In its defective
form, it permits high levels of the protein beta-catenin to
accumulate, which accelerates cell growth leading to polyps.
A non-inherited mutation of the APC gene occurs in nearly
all patients with sporadic colon cancer. (Sporadic in such
cases refers to the development of cancer without a strong
family history.) Various genetic mutations that affect the
APC gene directly or indirectly have been identified, including
Nonpolyposis Colorectal Cancer (HNPCC). Hereditary nonpolyposis
colorectal cancer (HNPCC), also known as Lynch syndrome, accounts
for 5% of all colorectal cancers. This abnormality occurs
in genes that error-check DNA. People who inherit the abnormal
gene have an extremely high risk of developing colon cancer.
HNPCC appears to be less aggressive and survival rates are
longer than for colon cancer that developed without known
risk factors. These cancers tend to develop in the right side
of the colon. People who inherit HNPCC are prone to other
cancers, including uterine and ovarian cancer.
Adenomatous Polyposis (FAP). In the rare disorder
familial adenomatous polyposis (FAP), the patient inherits
a mutated APC gene from his mother or father. In this
severe genetic disorder, thousands of polyps grow in the
colon during early adulthood. FAP causes less than 1%
of all cases of colorectal cancer, but if untreated, almost
everyone with this condition develops cancer before the
age of 40. Many of the deaths attributed to FAP could
be prevented with early and aggressive monitoring.
Gene. The AXIN2 gene interacts with the APC gene and
with beta-catenin. Researchers have shown that mutations
in this gene may cause a small percentage of colorectal
cancer and are trying to determine its role in cancer
Antitrypsin Gene. A mutation in a gene that causes
a deficiency in alpha-1 antitrypsin may increase the risk
for a certain subtype of colorectal cancer called MSI
(microsatellite instability) colorectal cancer. Alpha-1
antitrypsin is a substance that neutralizes protein-destroying
enzymes, and deficiencies may encourage cancer by allowing
chronic damage to cells. A genetic deficiency is a well-known
risk factor for emphysema and liver disease. The genetic
mutation has also been linked to liver and bladder cancer.
And research now suggests that it triples the risk for
the MSI subtype, which occurs in 15% to 30% of colorectal
cases. The risk in smokers with alpha-1 antitrypsin deficiency
is up to 20 times the normal rate.
1 and 2 (COX-1 and COX-2) are enzymes involved in the production
of prostaglandins, substances that regulate blood vessel narrowing
and opening and muscle contraction and inhibit hormones that
regulate fat metabolism. COX-2, but not COX-1, appears to
be a major suspect in the development and spread of colorectal
tumors. COX-2 increases the levels of prostaglandin E2 (PGE2),
which, in turn, stimulates factors that inhibit apoptosis,
the natural process whereby all cells, including cancerous
ones, self-destruct. It also induces interleukin-6 (IL-6),
a factor in the immune system that is associated with cancer
Cyclooxygenases and Prostaglandins
lifestyle, being sedentary, and excess weight have all been
associated with increased risk for colorectal cancer. Obesity
has been associated biologically with higher circulating levels
of insulin and a hormone called insulin-like growth factor
(IGF). Chronically high levels of these substances may increase
colorectal cancer risk.
Lifestyle Factors, Circulating Insulin, and Insulin-Like
Growth Factor (IGF)
Bile Acid Salts
Deoxycholic acid, which is found in bile, appears to have
carcinogenic properties. Its effects are now believed to play
a role in some cases of colon cancer. Increased levels of
the acid can develop with high-fat diets or in certain diseases.
It is possible
to have colon or rectal cancer without symptoms. Many patients
are free of symptoms until their tumors are quite advanced.
WHAT ARE THE SYMPTOMS OF COLON AND RECTAL CANCERS?
loss and changes in bowel movements are general symptoms for
colon cancer, but also occur in many other diseases.
Weight Loss and Changes in Bowel Movements
in the stools is a common sign of many intestinal cancers.
Blood in the stool may appear red if it is fresh or black
if it is old. Although it should be reported to a physician
immediately, it is often caused by conditions other than cancer,
including the following:
blood in stool is an abnormal finding that should never be
ignored. This always should be reported to your doctor for
Minor tears around the rectal or anal areas.
Stools can turn red after eating certain red foods, such
as beets or red licorice.
Iron supplements and medications that have bismuth subsalicylate,
most commonly Pepto-Bismol, can cause stools to turn black.
of colorectal cancer vary widely depending on the location
of the cancer within the large intestine.
Symptoms of Cancers in Specific Areas of the Colon
Tumors in the Cecum and Ascending Colon (Right Colon).
The waste matter in the first portion of the colon is
in liquid or semi-liquid form. Tumors that develop here do
not change bowel habits or stool formation, but they may cause
intermittent or chronic bleeding. Although the stools look
normal, patients may develop symptoms of anemia from iron
deficiency, which include weakness, fatigue, heart palpitations,
shortness of breath, and exercise intolerance.
Tumors in the Transverse Colon. As waste material passes
across the upper quadrants of the abdomen (the transverse
colon), the intestine absorbs water, and the waste matter
becomes more solid. In addition to bleeding, tumors here may
cause cramps, gas, partial or complete obstruction, and even
perforation of the bowel. Anemia as described above can also
Tumors in the Descending Colon and Rectum (Left Colon).
When tumors partially block the lower intestine, thin,
pencil-shaped stools may form. Bowel habits can change. Tumors
in the rectum and lowest part of the intestine can cause pain
and a feeling of fullness. Defecation may be painful or patients
may feel the urge to defecate, but nothing happens. Bleeding
from these locations may be brisk and bright red or maroon,
but cancer is often detected before symptoms of chronic anemia
people in the US are expected to be diagnosed with colon or
rectal cancer in 2001. The risks over all are equal in men
and women, but men have a slightly higher risk for rectal
cancers and women for colon cancers.
WHO GETS COLON AND RECTAL CANCERS?
colorectal cancers usually occur in people over 50. The rate
of colorectal cancer in patients under 20 years is less than
1 in 100,000 per year. At age 50 about 1 in 2000 people per
year will develop colorectal cancer, and after age 65, this
rate increases to almost 3 in 1000.
Americans are at higher risk of colon cancer. The highest
risks are in men of African descent, particularly in the sub-Sahara
region. The risk appears to be higher for colon but not rectal
cancer compared to Caucasians. 7
Ethnicity and Life Style
of patients under 45 years old and 15% of everyone who develops
colorectal cancer have a genetic risk. The average lifetime
risk of developing colorectal cancer is approximately 2%.
People who have a sibling or parent (first degree relative)
who developed colorectal cancer have three times (6%) the
lifetime risk of developing colorectal cancer. People who
have a first degree relative who developed colorectal cancer
before age 45 have an even higher, 10%, lifetime risk of developing
for colon cancer are far higher in industrialized nations
than less developed countries. Although a number of specific
risk factors have been identified, about 75% of cases occur
without a known predisposing factor.
Diet. Studies indicate that diets low in fruits and
vegetables and high in meats pose a risk for colon cancer.
Research also indicates that diets rich in fruits and vegetables
are protective against many cancers. [ See What Is
the Role of Diet in Colon and Rectal Cancers below.]
Alcohol and Smoking. Smoking may increase the risk
for colon cancer, and drinking alcohol regularly appears to
compound this risk. Nonsmokers who drink alcohol and have
diets rich in vegetables and fruits do not seem to have an
Obesity. There is a demonstrated link between body
mass and colon cancer risk for both men and women. The Centers
for Disease Control and Prevention reported in 1999 that the
risk of colon cancer rises as body mass index (BMI) increases.
Disease and Ulcerative Colitis. Crohn's disease and ulcerative
colitis are chronic afflictions of the large intestine known
as inflammatory bowel diseases (IBDs). Both have been linked
to increased risk for colorectal cancer. Family histories
are helpful in determining risk associated with inflammatory
bowel disease. Some studies suggest the following:
Other Intestinal Conditions
information, see the Well-Connected Report Inflammatory
Bowel Disease. ]
Patients with IBD who have a family history of colorectal
cancer face up to a five-fold risk of colon cancer themselves.
Individuals without IBD who have relatives who suffered
from both IBD and colorectal cancer may face a higher
risk for developing colorectal cancer themselves.
Individuals without IBD but with a family history of IBD
and no colon cancer most likely face no higher risk for
Ureterosigmoidostomy. People who have had ureterosigmoidostomy,
a surgical procedure to correct a birth defect in the bladder
or to treat some bladder cancers, may develop tumors near
the site of the implant, which is chronically exposed to urine
and feces. Such patients have a 5% to 10% chance of developing
colon cancer 15 to 30 years after the operation.
research suggested that diets low in fruits and vegetables
and high in meats pose a risk for colon cancer, and that those
rich in fruits and vegetables are protective against many
WHAT IS THE ROLE OF DIET IN COLON AND RECTAL CANCERS?
study by Harvard researchers concluded that eating fruits
and vegetables had little or no effect on colorectal cancer
rates. These findings contradicted prevailing belief in the
medical community and previous studies that found an association
between a high intake of these foods and a lower risk for
colorectal cancer. For example, early results in 2000 of the
European Prospective Investigation into Cancer and Nutrition
(EPIC) have suggested that a diet high in fruits and vegetables
can help prevent colorectal cancer. This is the largest study
ever conducted on the role of diet in the development of cancer.
Plant Chemicals (Phytochemicals) Found in Fruits and Vegetables
Phytochemicals. Many studies have demonstrated the
cancer-fighting effects of plant chemicals called phytochemicals.
Fruits and vegetables that contain phytochemicals can often
be identified by colors:
Carotenoids are red, yellow, and orange pigments found
in some animal tissues and in many fruits and vegetables.
Carotenoids being investigated include the following:
Dark green (broccoli, spinach, kale, collard greens, mustard
Red (red pepper, tomatoes, watermelon, raspberries, pink
Yellow-orange (carrots, pumpkin, sweet potatoes, oranges,
and Indoles. Isothiocyanates and related substances, indoles,
are also known as mustard oils and are responsible for the
sharp taste in cruciferous vegetables (broccoli, cabbage,
Brussels sprouts, cauliflower, collards, kale, kohlrabi, mustard
greens, rutabaga, turnips, bok choy). When digested, indoles
yield 3,3'-diindolylmethane (DIM). DIM appears to fight cancer
in laboratory tests by stopping malignant cells from dividing
and multiplying, and by affecting levels of proteins that
affect tumor cells. Whether this has implications in humans
Lutein (found in spinach, broccoli, lettuce, tomatoes,
oranges and orange juice, carrots, celery, and greens)
may protect against colon cancer among the general population,
although the benefits may not be significant for individuals
with a family history of the disease.
Lycopene (found in tomatoes and other red fruits and vegetables)
may have strong cancer-protective properties. Cooking
tomatoes appear to increase their benefits.
High intakes of other carotenoids (including alpha-carotene,
beta-carotene, lycopene, zeaxantin, and beta-cryptoxanthin)
did not appreciably affect colon cancer risk in another
Lectin. Lectin, which is found in broad beans and mushrooms,
may also be protective.
Organosulfur Compounds. Organosulfurs are part of the
allium family of phytochemicals. They may have benefits on
the immune system, assist the liver in rendering carcinogens
harmless, and reduce production of cholesterol in the liver.
These compounds are found in garlic, leeks, onions, chives,
scallions, and shallots. Two recent studies drew conflicting
conclusions about the preventive effects of garlic. A review
of 300 studies concluded that people who eat raw or cooked
garlic regularly experience about two-thirds the risk of colorectal
cancer as people who eat little or none. Another analysis
found the available evidence about garlic to be inconclusive,
however. Garlic supplements, in any case, do not appear to
of studies have shown that fiber protects against colon cancer,
but recent research contradicts this long-held belief. Two
studies reported no difference in the development of colorectal
polyps with high or low intake of fiber. These studies did
not report on overall effects on cancer itself, though one
would expect there to be no difference. Different fiber forms
may also have different effects on tumor growth, which the
studies did not address. One study, in fact, suggested that
fiber supplements containing the ispaghula husk may actually
increase the risk for tumors. This substance is similar to
psyllium, another common fiber supplement. In any case, fiber,
which is only found in plant products, may be beneficial for
the heart and have other health advantages.
A number of studies have found an association between
saturated fats (found primarily in animal fats) and colon
cancer. Olive oil, however, may be protective according to
a study of 28 countries. Some evidence suggests that it reduces
levels of deoxycholic acid, an acid found in bile that has
tumor-promoting properties. Researchers in the study suggested,
in fact, that the protective role in fruits and vegetables
observed in various studies may simply be due to a high intake
in olive oil in the same people who consumed large amounts
Fats and Meat
Meat. Some evidence suggests that it is only the particular
type of fatty acid found in red meat, not all animal fat,
that raises the risk for colon cancer. Red meat may increase
levels of deoxycholic acid, a bile acid associated with colon
cancer. In fact, early results in 2000 from the largest study
on diet and cancer to date have supported previous studies
linking red meat with intestinal tumors.
High-temperature cooking (grilling or pan frying) has been
specifically associated with increased risk for colon polyps.
Over-cooking meat increases the amount of carcinogens called
heterocyclic amines, although whether they or any other chemical
released with grilling pose any significant risk for cancer
is as yet unproven.
analysis suggested that milk, particularly fermented milk
(buttermilk, yogurt), may have compounds or bacterial culture
that help protect against colon cancer. Calcium, which is
found in dairy products, is also associated with colon cancer
Dairy Products and Calcium
Lactic Acid Bacteria Cultures. There is some evidence
that consumption of lactic acid bacteria cultures called lactobacilli
may suppress cancer. Such bacteria must be probiotic. That
is, they must be able to reproduce in the intestinal tract.
Many brands of yogurt and other fermented dairy products contain
probiotic bacteria, such as acidophilus. People should look
for labels that identify active cultures. Acidophilus capsules
are available in health food stores.
Calcium. Most studies show a protective effect from
high-calcium diets or calcium supplements, but the association
is statistically significant in only a few studies. The protective
effect has been observed as early as one year after calcium
research suggests that soy protein may help prevent colon
cancer. A small 1999 study suggests that soy protein reduces
the incidence of colon cancer in people who have a history
of the disease or who have had pre-cancerous polyps removed.
studies of people under 67 years old, the amounts of fat and
protein were less important than the total number of calories
consumed: the higher the energy intake, the greater the risk
for developing colon cancer. In older adults, high calorie
intake did not make any significant difference. Other studies
have indicated that excessive sugar-intake may increase the
risk for colon cancer.
Sugar and Total Calories
conducted in a number of countries have found that drinking
four or more cups of coffee a day is associated with a lower
risk for colorectal cancer. Green tea may have beneficial
properties, but more research is needed in both of these areas.
Coffee and Tea
evidence that the B vitamin folate (called folic acid) is
protective. Both folate and vitamin B12 convert the amino
acid homocysteine to methionine, a chemical that protects
certain genes that help prevent cells from becoming malignant.
Folate is found in beans, citrus fruits, and green vegetables,
but benefits seem higher when taking supplements. The protective
effect appears to be greatest for people who are genetically
predisposed to colorectal cancer.
The role of vitamins in colon cancer is unclear. Some studies
have associated supplements of vitamins A, C, D, and E with
lower colon cancer risk, but other studies have found no protective
is a trace element in meats, whole grains, egg yolks, fish,
and some other foods, such as Brazil nuts. In one study, people
who took a daily selenium supplement of 200 micrograms for
more than four years had half the rate of lung, colon, rectal,
and prostate cancer as those who did not. The study had limitations,
however, and high amounts can be toxic, causing hypothyroidism
and hair and nail loss. The overall health benefits of selenium
are still unknown
WHAT ARE NON-DIETARY MEASURES FOR PREVENTING COLON AND RECTAL
anti-inflammatory drugs (NSAIDs) have been shown to decrease
the frequency of colorectal cancer. A number of studies have
suggested that taking NSAIDs at doses similar to those taken
by arthritic patients for pain protection confers protection
against colon cancer.
Nonsteroidal Anti-Inflammatory Drugs (NSAIDs)
Protective NSAIDs. There are many NSAIDs available,
including aspirin, ibuprofen (Motrin, Advil, Nuprin, Rufen),
and naproxen (Aleve). Taking any NSAIDs for short periods
of time is not protective. However, long-term use of NSAIDs
to prevent colorectal cancer is not yet recommended. The following
are some NSAIDs and NSAID combinations of particular interest:
It should be noted that NSAIDs, even in low doses, can cause
gastrointestinal bleeding and ulcers in some people. In fact,
studies estimate NSAID-related deaths in the United States
at 10,000 to 20,000 per year, and NSAID-related hospitalizations
at 100,000 per year. COX-2 inhibitors may have fewer of these
side effects, although long-term studies are still needed.
COX-2 inhibitors, celecoxib (Celebrex) and rofecoxib (Vioxx)
block the enzyme cyclooxygenase-2 (COX-2), which has been
particularly associated with cancer risk [ see
Cyclooxygenases and Prostaglandins above]. Early
studies indicate that celecoxib may help prevent new growth
and retard the growth of existing polyps. Celecoxib has
now been approved for patients with familial adenomatous
Studies report that the potent NSAIDs indomethacin and
sulindac caused regression of rectal polyps in people
with FAP. The polyps most likely resume progression when
the drugs are stopped.
Combining NSAIDs with the cholesterol-lowering drugs known
as statins (lovastatin, pravastatin, simvastatin) in some
studies, has significantly lowered the rate of colon cancer
compared to taking NSAIDs alone. Experts are hoping that
such combinations may allow lower NSAIDs dosages, thereby
reducing the risk for gastrointestinal side effects. This
combination, however, requires further study.
have indicated that regular, even moderate, exercise (30-minute
daily jog or 60-minute daily walk) reduces the risk of colon
cancer. Regular activity may be the most important lifestyle
component in decreasing colon cancer risk. Strenuous activity
adds only slight or no additional benefit.
Replacement Therapy. Studies continue to show that hormone
replacement therapy, with or without progesterone, protects
against colon cancer. Risk reduction for colon cancer is also
associated, however, with a healthy lifestyle, and it is still
not yet known whether estrogen protects against colon cancer
or if, rather, women who take HRT tend to be healthier. HRT
carries certain risks and other benefits that women should
discuss with their physician.
Estrogen in Women
Oral Contraceptives. Use of oral contraceptives may
reduce women's risk of colon cancer. Duration of use does
not seem to be associated with decreased risk, but protection
appears stronger for women who have used oral contraceptives
is a drug sometimes used to treat gallstones or a rare inflammation
of the bile ducts associated with ulcerative colitis. It helps
reduce deoxycholic acid levels, an acid that has tumor-promoting
properties. Studies now suggest it may prevent colon cancer
in persons at high risk. More research is needed.
rectal cancers are diagnosed using the screening tests discussed
below. These tests can detect premalignant polyps and colorectal
cancers at stages early enough for complete removal and cure.
Unfortunately, only a minority of adults over 50 years old
(mostly in the upper socioeconomic group) have regular screening
tests that could detect a cancer early enough for curative
treatment. A survey reported that many people are not screened
because they are too embarrassed and revealed that they would
rather lose months off their life than face these tests. Those
who had already had the tests were willing to have them again
if they saved one additional day of their lives. There is
some debate about what is the best screening modality. However
almost all experts agree that not enough people are screened.
[ See Box General Screening Guidelines.]
HOW ARE COLON AND RECTAL CANCERS DIAGNOSED?
GENERAL SCREENING GUIDELINES
should discuss with their physician the risks and benefits
of all screening procedures. Some controversy exists
over how often people without risk factors for cancer
should be screened and which detection method should
be used for them.
Guidelines for Adults Age 50 and Over with Average
at age 50 and over who have no symptoms and no family
history of colon cancer (or possibly also no family
history of benign polyps) should have the following:
between Colonoscopy and Sigmoidoscopy. The choice
between the use of colonoscopy and sigmoidoscopy for
routine screening for older adults with average risk
is, in fact, an area of intense debate. The issues are
An annual digital rectal exam (DRE) and fecal occult
blood test (FOBT). A follow-up colonoscopy follows
any questionable results.
A flexible sigmoidoscopy every five years is the
standard recommendation. A follow-up colonoscopy
is conducted if sigmoidoscopy reveals multiple polyps,
polyps that show precancerous signs, or polyps larger
than 6 millimeters.
A colonoscopy or double barium enema might be considered
instead of sigmoidoscopy every five to ten years.
(When using a barium enema, a colonoscopy should
follow any questionable results.)
it is clear that colonoscopy is more sensitive than
other methods for detecting colon cancer, it has a higher
rate of complications and cost. Most polyps found during
an examination are not cancerous. It is not cost efficient
to use colonoscopy as standard screening for everyone
over 50, but some experts now recommend that it be routine
for any high-risk and older patients.
Sigmoidoscopy is less costly and invasive than colonoscopy,
but it allows inspection only of the left side of
the colon. (African American men, for example are
more likely to have left-sided colon cancers.)
A 2000 study reported a decline in left-sided colon
cancer with increased use of sigmoidoscopy screening,
but also indicated that further declines would occur
if widespread colonoscopy were used.
Two studies in 2000 suggested that sigmoidoscopy
is likely to miss growths in as many as 20% to 30%
of those who have them.
A landmark 1993 study reported an approximate 90%
reduction in colorectal cancers in patients with
pre-cancerous polyps who were regularly screened
with colonoscopy and who had all colonic polyps
removed. And, no deaths were reported from cancers
that were detected during screening.
Guidelines for Increased-Risk Groups
at increased risk include the following:
individuals should consider beginning the standard screening
regimen with a colonoscopy every five years beginning
at age 40 or ten years before the youngest case in the
family (whichever is earlier).
Men of African descent (particularly from sub-Sahara
Men with first-degree relatives diagnosed with colon
cancer younger than 60.
Guidelines for High-Risk Groups
following guidelines may be specifically useful for
2000 study indicated that screening, particularly with
colonoscopy, in this population can significantly save
lives. For example, a 2000 study concluded that colonoscopy
can reduce risk of colorectal cancer and death in individuals
at risk for HNPCC by up to 65%.
People with a family history of FAP. DRE and colonoscopy
beginning at age 10. Consider genetic testing.
People with a family history of HNPCC. The same
tests as those with FAP performed beginning at age
21 (some recommend adolescence). (It should be noted
that colonoscopy should always be used in this group.
About 72% of hereditary nonpolyposis colorectal
cancers are out of the view of a sigmoidoscope.)
People with predisposing intestinal problems such
as widespread and active ulcerative colitis or Crohn's
disease. Annual screening with colonoscopy with
biopsies of suspicious areas.
Guidelines for Follow-Up after Detection of Precancerous
who have had a previous examination in which polyps
were detected (and removed) should have a repeat colonoscopy
one to three years later, depending on the size, number,
and type of polyps removed.
Digital Rectal Examination (DRE)
rectal examination is used to detect tumors in the rectum,
lower intestine, and prostate gland. The doctor inserts
a lubricated-gloved finger into the patient's rectum and
feels for lumps or other abnormalities. The exam is quick
and painless but embarrassing for some and will only detect
a minority of cancers.
bowel movements is not always visible, in which case it is
called occult blood. Fecal occult blood tests (FOBT) are used
to detect this hidden blood. The most common FOBT method is
called the guaiac-based test. The patient is asked to supply
up to six stool specimens in a specially prepared package.
A small quantity of feces is smeared on specially treated
paper, which reacts to hydrogen peroxide. If blood is present,
the paper turns blue.
Fecal Occult Blood Tests (FOBT)
Accuracy. Some experts argue that FOBTs miss too many
cancers and should not be relied on. Controversy has been
on-going as to whether this test is too inaccurate to be very
beneficial, both in missing cancers and in showing false positive
results that lead to invasive and expensive tests, most of
which turn out to be unnecessary. Large studies, however,
have indicated that this simple test does indeed save lives
and may reduce the risk of dying from colon cancer by 15%
The following may affect results:
none of these conditions is present, a test that shows hidden
(occult) blood does not necessarily mean that cancer is present.
About 20% to 30% of people with occult blood have noncancerous
polyps or other conditions, such as gastritis, and only 5%
to 10% actually have cancer. Any abnormal result, however,
requires further testing such as colonoscopy [ see below
The levels of iron in the blood can affects results. Patients
should not take iron supplements or eat red meats several
days before the test.
Certain raw fruits and vegetables, including cauliflower,
horseradish, radishes, melons, and turnips, that contain
the chemical peroxidase can cause a positive test reaction
even if no blood is present.
Aspirin and other NSAIDs can cause minor bleeding and
should not be taken for a week before the test.
Vitamin C and foods rich in this vitamin may cause a false
negative reaction and should be avoided a few days
before the test.
Bleeding from other causes, such as menstruation, hemorrhoids,
gingivitis, or urinary infections, can produce blood in
the stools and affect results.
Lack of Compliance. Compliance is a major problem.
Patients are asked to perform the tests at home and send the
test cards to the laboratory; only 35% to 50% of patients
actually follow through. Occult-blood tests that give results
at home are available but are extremely inaccurate. In one
large study, these tests failed to detect advanced cancer
in about 62% of cases, although they may detect some early
If a digital
rectal exam (DRE) or fecal occult blood test (FOBT) show signs
of trouble, several methods to visualize the colon are available.
They include colonoscopy, sigmoidoscopy, and double-contrast
barium enema. They have the following similarities and differences:
Visualizing the Colon: Colonoscopy, Sigmoidoscopy, and Barium
Sigmoidoscopy examines the rectum and the lower two feet
of the colon. It cannot detect right-colon cancers.
Sigmoidoscopy can only view the rectum and the left side
of the colon, while colonoscopy and barium enemas allow
a view of the entire large intestine.
Both flexible sigmoidoscopy and colonoscopy involve snaking
a fiberoptic tube through regions of the rectum and colon
to view the walls of the intestine. Barium enemas simply
During either sigmoidoscopy or colonoscopy, the physician
is able to remove polyps or other abnormalities revealed
by these procedures. This is not possible using a barium
has been found to reduce the risk of fatal cancers in the
rectal and sigmoid area by 60%. If polyps are detected, a
colonoscopy is then used.
The procedure employs a flexible fiberoptic tube that
contains a tiny camera and surgical instruments.
It lasts about 10 minutes and may be mildly uncomfortable,
but it is not painful. In one study, 70% of patients reported
that the procedure was far less unpleasant than they had
Colonoscopy. A colonoscopy, as with sigmoidoscopy,
uses a flexible tube but it is snaked through the entire large
are rare, but include the following:
For about a day before the procedure the patient eats
nothing and drinks a solution that essentially cleans
out the colon. Patients often complain about the taste
of the solution.
The procedure typically uses a sedative that produces
a "twilight" sleep and often makes the procedure more
comfortable than sigmoidoscopy.
Air may be introduced into the intestine to widen it and
allow the tube to navigate curves. A colonoscopy avoids
the risk of radiation associated with a barium enema [
see below ], but it should be noted that even a
colonoscopy does not detect all cancers.
Enema. The double-contrast barium enema, which uses an
x-ray image, is the less expensive alternative for viewing
the entire colon. It is not as accurate as colonoscopy [ see
above ], and if any polyps or abnormalities are revealed
on x-ray, a colonoscopy is then required to remove suspicious
Hyponatremia. Hyponatremia is a low concentration of sodium
in the blood. The complication may be caused by the effects
of bowel cleaning before the procedure that can result
in water retention and reductions in sodium. When severe,
it can cause temporary neurological symptoms, such as
confusion, lethargy, unsteadiness, and slurred speech.
Researchers suggest that sodium concentrations be measured
in patients who develop such symptoms after colonoscopy.
Bowel perforation (very low risk).
DNA Testing. A promising technique for colorectal cancer
screening is the detection of altered DNA in cancer cells
that have shed from the colon and are excreted in the stool.
This may become a widely used tool in the future, however
larger clinical studies are needed.
Experimental Screening and Diagnostic Methods
Virtual Colonoscopy. Another promising experimental
technique called virtual colonoscopy allows three-dimensional
imaging of the colon without using invasive instruments. The
procedure involves pumping air into the colon and scanning
it using computed tomography (CT). The procedure is very safe
and takes only 10 minutes. This procedure is similar in accuracy
to conventional colonoscopy for detection of larger polyps
(6 mm or more in diameter) and is also potentially less expensive.
Colonoscopy is required, however, if suspicious areas are
found, which may occur frequently with the CT procedure, since
it erroneously identifies a high number of nonexistent polyps.
Magnetic Resonance Colonography (MRC). Magnetic resonance
colonography (MRC) is another non-invasive technique for visualizing
the colon. The patient receives an enema containing a contrast
agent, then magnetic resonance images are taken. MRC is fast,
comfortable, and less invasive than colonoscopy. Currently,
however, there is a poor detection rate for flat tumors and
for polyp tumors less than 10 mm in diameter.
of cancer will lead to staging and other tests to help determine
the outlook and the appropriate treatments.
HOW IS A PROGNOSIS FOR COLON AND RECTAL CANCERS DETERMINED?
many other cancers, the size of the tumor is not a major factor
in determining the outcome of colorectal cancer. Of greater
importance is how far the cancer has spread. To determine
this, physicians will assign a stage to the tumor. There are
several methods for staging. The older system, known as Dukes',
categorizes four basic stages: A, B, C, and D. A more recent
system refers to these stages as I, II, III, and IV but divides
the categories slightly differently. The term "five-year survival";
means that patients have lived at least five years since diagnosis.
Most patients who live five years without a recurrence are
cured of their disease.
A or I
Tumor superficially involves the inner lining of the
More than 90%
B or II
Tumor has penetrated through the muscle wall of the
intestine but has not reached the lymph nodes.
70% to 85%
C or III
Lymph nodes are involved.
65% or below
D or IV
Tumor has spread to other organs (metastasized), usually
the liver first. Disease is generally considered incurable.
are continually seeking to identify tumor markers (elevated
substances usually found in blood samples) that will assist
in diagnosis of cancer and in monitoring effects of treatment.
Carcinoembryonic Antigen (CEA). High blood levels of
a protein called carcinoembryonic antigen (CEA) sometimes
indicate the presence of colon cancer. Unfortunately, it is
also elevated in other cancers and in some noncancerous conditions.
CEA is not effective as a screening tool for healthy people,
but might eventually be helpful for cancer patients.
P53 Gene. The presence of a defective p53 gene is a marker
for very poor prognosis in patients with advanced colon cancer.
In its normal state, the gene is important for regulation
of cell growth. Testing for this abnormality however is not
widely done because it is not clear how to use this information.
An advanced diagnostic technique called polymerase chain
reaction (PCR) can detect genetic evidence of CEA. One
study indicated that when these microscopic footprints
of colon cancer are detected in the lymph nodes of Stage
II patients (whose lymph nodes otherwise appear to be
not involved with cancer), the outlook is similar to that
of Stage III patients. Patients without this so-called
micrometastasis have a very favorable prognosis. Further
research is needed however before this technique can be
used in widespread practice.
In patients with a history of or active colon cancer,
follow-up measuring of blood CEA levels may be helpful
in detecting recurrence of the cancer and effectiveness
Other Tumor Markers. Other tumor markers under investigation
are a protein called GLUT1, cancer antigen 19-9 (CA 19-9),
matrix metalloproteinase-9 (MMP-9) RNA, HER-2/neu oncoprotein,
and CD44, however their role is unknown and they should not
be used outside the setting of a clinical study.
people are expected to die from colorectal cancers in 2001.
Only lung cancer is responsible for more cancer deaths. This
occurs despite the fact that colorectal cancer is almost always
a preventable or curable disease when proper screening is
HOW SERIOUS ARE COLON AND RECTAL CANCERS?
survival rate for patients undergoing colon cancer surgery
is as high as 90% for cancer that has not spread to the lymph
nodes. When cancer has spread to lymph nodes, survival rates
drop to 65% and below. Because many cancers are detected at
later stages, the overall survival rate is currently about
cases age is not a factor in treatment success; good survival
rates are achieved in the elderly as well as in young people.
Chances for survival are less in stage II cancers if the intestine
is obstructed or perforated. If cancer has spread to lymph
nodes (Stage III), the outlook is better if three or fewer
lymph nodes are involved. It is important to note that treatment
can prolong life even when cancer has spread.
Factors in Treatment Success
removal of the tumor along with any affected surrounding tissue
is the standard initial treatment for potentially curable
colorectal cancers (cancers that have not spread beyond the
colon or lymph nodes). Drug therapy, radiation, or both are
often used for advanced cancers and are continuously being
tested with surgery in different combinations and sequences.
[ See sections What Are the Drug Treatments for Colon
and Rectal Cancers? And What Is Radiation Treatment for Rectal
WHAT ARE THE SURGICAL TREATMENTS FOR COLON AND RECTAL CANCERS?
Although choosing a qualified surgeon is critical, choosing
a hospital experienced in procedures is also important. According
to a 2000 study, the more often colon cancer surgery is performed
at a given hospital, the lower the mortality rate at that
hospital is likely to be. The 30-day postoperative mortality
rate for patients treated at hospitals in the top quartile
of procedure volume was 3.5%. For hospitals in the bottom
quartile, mortality was 5.5%. However, the differences were
small, and significantly less than seen for more complex cancer
Stage I lesions, or for cancers that have gone beyond the
mucous membrane and have penetrated into or through the intestinal
wall, an operation known as colectomy is the standard treatment.
Colectomy involves removing the cancerous part of the colon
and nearby lymph nodes and then reconnecting the intestine
by a procedure known as anastomosis. If the surgeon
cannot reconnect the intestine, usually because of infection
or obstruction, a colostomy is performed [ see below
]. The need for colostomies is higher after surgery for
rectal cancer. In most cases of colon cancer, colostomies
are not needed.
The Surgical Approach. The open procedure involves
an abdominal incision and is the standard method for performing
colectomy. Laparoscopy is a more recent and investigative
approach. It employs a few small incisions through which the
surgeon passes a fiber optic tube containing a small camera
or tiny instruments. When performed by an experienced surgeon,
laparoscopy for selected patients may be equal to open surgery
in effectiveness. One study suggested that patients in early
stages with any tumors less than 2 centimeters or with well-defined
tumors less the 3 centimeters might be candidates for laparoscopic
colon surgery. This procedure is still under investigation,
however, and should only be performed in clinical trials or
in special circumstances by experienced surgeons.
connects the colon to a hole through the abdominal wall, called
a stoma, through which the feces are eliminated. A
colostomy may have one opening (single-barreled), or there
may be two loops opening through the skin (double-barreled).
Usually the colostomy is temporary and can be reversed by
a second operation. Patients must learn how to care for the
stoma and keep the area sanitary.
Permanent Colostomies. In cases where the colostomy
is permanent, the patient must wear a colostomy pouch, which
sticks to the skin using a special glue. Men tend to have
more emotional difficulties dealing with permanent colostomies
than women do. In one study, the four major concerns after
treatment were the following:
(1) Fear of being unable to take care of themselves.
(2) Leakage from the pouch, odor, and gas.
(3) Other health problems.
(4) Recurrence of cancer.
treatments for cancer in the rectum are complex since they
involve muscles and tissue that are critical for urinary and
Surgical Treatments for Rectal Cancer
Local Excision or Polypectomy for Early Stages. In
order to preserve the function of the anal sphincter and prevent
the need for colostomy, stage I and stage II tumors may be
removed by local excision, sometimes followed by chemotherapy
and radiation. In this procedure, the tumor is cut out without
removal of a major section of rectum. Another treatment for
early-stage rectal cancer, electrocoagulation (destroys tumors
using a high frequency electric current) is being tested but
should only be used in the setting of clinical trials.
Radical Resection. In about a third of cases of rectal
cancer, the cancer occurs in the lower part of the rectum,
where between 70% and 80% of cancers have spread beyond the
rectal wall. In such cases, a radical resection is required,
in which surrounding structures, including the sphincter muscles
that control bowel movements, must often be removed. The use
of chemotherapy and radiation prior to surgery may prevent
the need for permanent colostomy in some patients. This is
an active area of clinical research and current trials are
underway to address this issue. An alternative technique called
coloanal anastomosis reconstructs the area to avoid the need
for colostomy, and may be appropriate in selected patients.
Total Mesorectal Excision. Total mesorectal excision
(TME) involves dissection and removal of the entire cancerous
area of the rectum along with surrounding fatty regions where
the lymph nodes are located (the mesorectum). When successful,
TME preserves the sphincter muscle, reducing the need for
a permanent colostomy. Studies have also suggested lower recurrence
rates, lower levels of impotence and incontinence, and better
overall survival rates compared to other resection techniques.
Some experts now recommend that it be the first choice for
certain patients with locally advanced rectal cancer. Combining
pre-operative chemotherapy and radiation with TME is yielding
promising long-term results and a low risk for local recurrence.
of colon surgery include:
Side Effects and Psychological Repercussions
side effects of sexual and bowel dysfunction for colorectal
surgical patients can be devastating, although many patients
do very well and live normal productive lives. Colon cancer
patients without a colostomy are at lower risk for these problems
than patients with rectal cancer whose sphincter muscles are
affected, but no one is immune to the psychological repercussions
of cancer and its consequences. Positive emotions play a strong
role in recovery. Patients who are depressed should discuss
with a physician all aspects of treatment that affect the
quality of life and possibly seek support groups.
irregular bowel movements,
sense of urinary urgency, and
WHAT ARE THE DRUG TREATMENTS FOR COLON AND RECTAL CANCERS?
uses drugs that kill cancer cells throughout the body. There
are two situations in which chemotherapy is used:
adjuvant setting, there are some differences in chemotherapy
treatments between colon and rectal cancers:
The adjuvant setting. Adjuvant refers to the use of chemotherapy
after surgery in patients with stage II and stage III
tumors (patients who are curable). The goal of this therapy
is to eliminate any cancer cells that surgery may have
missed, thereby preventing recurrence and increasing the
chance of cure.
In metastatic disease. In patients with metastatic disease
the goal of chemotherapy is to shrink tumors, improve
symptoms and quality of life, and to lengthen life. [
See What Are the Treatment Options for Metastasized
for Stage II Patients with Colon Cancer. Adjuvant chemotherapy
for Stage II colon cancer patients is controversial. Such
patients tend to have a good outcome after surgery and the
positive effects of chemotherapy have been difficult to demonstrate.
A 1999 combined analysis of four studies showed a 30% reduction
in death rate from the use of adjuvant chemotherapy in these
cancer patients. A more recent 2001 survey, however, found
no significant survival differences. In the study, 5-year
survival was 74% with chemotherapy and 72% without it. The
researchers believe that patients not treated with chemotherapy
should have the same level of confidence as those given these
agents. The decision whether to pursue chemotherapy for stage
II disease should be made after careful discussion between
the patient and his or her oncologist.
Chemotherapy for Stage II patients is considered standard
care for stage II rectal cancer but is under debate for
Chemotherapy alone is standard for stage III colon cancer
patients. Chemotherapy is also standard for stage III
rectal cancer patients but is used in combination with
Chemotherapy uses for stage IV colon and rectal cancer
are essentially the same and are discussed together.
Although not yet known with certainty, some data suggest that
specific Stage II patients may be at higher risk of recurrence
and would theoretically benefit from adjuvant therapy. These
include the patients with the following conditions:
diagnostic techniques are under investigation for helping
to select appropriate Stage II candidates for adjuvant therapy.
Among them are the following:
Cancers that have obstructed the bowel,
Cancers that have perforated the wall of the colon, or
Cancers that have adhered to structures outside the intestine.
these methods, however, are ready to be used routinely to
help make treatment decisions.
A test that can detect genetic evidence of cancer cells
in the lymph nodes of Stage II patients. Their presence
would suggest the need for treatment.
A test called the liver Doppler perfusion index (DPI),
which measures blood flow to the liver. A high DPI score
suggests liver involvement and therefore might indicate
a need for more aggressive treatment.
There are also many genetic markers that are being developed
which may help identify patients at higher risk.
Chemotherapy for Stage III Patients with Colon Cancer.
Since the early 1990s, adjuvant chemotherapy with 5-FU
and leucovorin has been the standard of care for stage III
colon cancer. Numerous trials have shown that adjuvant chemotherapy
in this setting reduces the absolute risk of death from colon
cancer by approximately one third. Current clinical trials
are investigating whether the addition of new chemotherapy
drugs (irinotecan, oxaliplatin, and antibody therapies) will
improve cure rates over 5-FU and leucovorin along. However,
these new agents should currently not be used for adjuvant
treatment of colon cancer unless as part of a clinical trial.
Chemotherapy for Advanced Colorectal Cancer. Chemotherapy
and radiation are generally used to reduce symptoms and prolong
life in advanced colorectal cancer. Chemotherapy in most studies
offers a modest improvement in survival and often relieves
symptoms. Some experts suggest that chemotherapy should be
considered for the following patients:
patients are unlikely to benefit from chemotherapy:
Able to carry out all normal activity without restriction.
Restricted in physically strenuous activity but able to
walk about and carry out light work.
Able to walk about and capable of all self care but unable
to carry out any work. Out of bed or chair for more than
50% of waking hours.
chemotherapeutic drug, 5-fluorouracil (5-FU), is used alone
or with other drugs, most commonly leucovorin. Patients should
seek clinical trials with immunotherapies and other new chemotherapy
Capable only of limited self care. Confined to bed or
chair for more than 50% of waking hours.
Severely disabled. Cannot carry out any self care. Totally
confined to bed or chair.
(5-FU) with Leucovorin. Adjuvant therapy using 5-fluorouracil
(5-FU) with leucovorin is currently the standard treatment
for patients with high-risk colon cancer (Stage III or selected
patients with Stage II tumors). Leucovorin, also called folinic
acid, is a form of the B vitamin folic acid. Patients are
given a serious of cycles that usually continue for at least
six months. 5-FU is given intravenously at present, but oral
preparations are currently being tested in clinical trials.
Research in Spain indicates that home chemotherapy programs
can increase compliance and patient satisfaction. There are
many different ways of giving 5-FU including intravenously
over several hours once a week, intravenously daily for five
consecutive days every month, or as continuous infusion with
a portable pump. The side effects can be quite different depending
on the way 5-FU is given. Most patients tolerate 5-FU with
leucovorin well, with manageable side effects.
Specific Chemotherapy Agents
Irinotecan. Irinotecan (Camptosar). Irinotecan inhibits
an enzyme essential for cell division and works in combination
with 5-FU. When it was approved in the mid 1990s, it was the
first new drug developed for colon cancer in over 30 years.
Two studies reported in 2000 have shown that a combination
of irinotecan along with 5-fluorouracil and leucovorin (5-FU/LV)
significantly delays the time at which tumors progress and
improves survival in metastatic cancer compared to 5-FU/LV
alone. While this survival advantage is small, the combination
has become the standard of care for metastatic cancer for
many oncologists. Of concern, however, were 2001 studies reporting
an increased risk of death from toxic effects with the use
of the three-drug combination. Experts recommend careful monitoring
and alternative methods for administrating the drugs.
Capecitabine. Capecitabine (Xeloda) is the first oral
agent approved for metastatic colorectal cancer. It allows
fewer days of hospitalization and side effects are manageable.
Compared to standard therapy, capecitabine has demonstrated
similar results, although combinations with 5-FU are being
Oxaliplatin. Oxaliplatin is variant of cisplatin, a
widely used platinum-based chemotherapy drug. The drug appears
to be active in some patients with metastatic colorectal cancer
who have failed treatment with 5-FU and irinotecan. Oxaliplatin
can cause a unique peripheral neuropathy (abnormal sensations
in the hands and feet) that is exacerbated by exposure to
cold. The drug has been widely used in Europe but was rejected
for approval by the FDA in 2000. Many investigators objected
to this decision, and current trials using oxaliplatin in
stage II, III, and IV colon cancer are underway.
Raltitrexed. Raltitrexed (Tomudex) may be as effective
and less toxic than the 5-FU and leucovorin combination. Preclinical
studies indicate that raltitrexed and 5-FU may have additive
or synergistic effects.
occur with all chemotherapeutic drugs; they are more severe
with higher doses and increase over the course of treatment.
Because cancer cells grow and divide rapidly, anticancer drugs
work by killing fast-growing cells. This means that healthy
cells that multiply quickly can also be affected. The fast-growing
normal cells most likely to be affected are blood cells forming
in the bone marrow, and cells in the digestive tract, reproductive
system, and hair follicles.
Side Effects of Chemotherapy
Side effects vary specifically with different drugs, but,
in general, they include the following:
effects are nearly always temporary. Most patients are able
to continue with normal activities for all but perhaps one
or two days a month.
Nausea and vomiting.
Diarrhea (very common with 5-FU).
Temporary hair loss (usually minimal with 5-FU).
Pain and redness of the hands and feet.
More serious complications can also occur and may vary depending
on the specific agents used. They include the following:
Increased chance for infection (from suppression of the
uses the body's own disease fighters to attack the cancer.
These agents hold promise for adjuvant therapy of colorectal
cancer but are still under investigation. Some approaches
enhance the body's defense systems; others use genetic engineering
techniques to design molecules that target and attack tumor
Monoclonal Antibodies . Of particular interest are
specially-developed immune factors called monoclonal antibodies,
which attack specific proteins located in colon cancer cells.
Cetuximab (IMC-C225), for example, binds to a growth receptor
which colon cancer cells require in order to proliferate.
A 2001 study reported that 48% of patients with metastatic
colon cancer who had failed both 5-FU and irinotecan responded
to a combination of cetuximab and irinotecan. Another monoclonal
antibody, edrecolamab, had shown promise in early studies,
but a 2001 clinical trial reported no survival benefits. No
monoclonal antibody is curative.
Radioimmunotherapy. Researchers are investigating radioimmunotherapy,
the use of monoclonal antibodies to deliver radioisotopes
(radioactive material) to colon cancer cells and destroy them.
Radioimmunotherapy may already be a viable therapeutic option
for colorectal cancer patients with limited disease. Studies
have been disappointing on its effect on larger or bulky tumors.
are investigating so-called "suicide gene"; therapy, which
experts hope will prevent colon cancer from spreading to the
liver. The therapy uses a gene from bacteria to convert a
prodrug, a nontoxic compound with no anticancer effects, into
a cancer-killing agent within the liver. While promising in
animals, human trials have been disappointing to date. Research
is ongoing to improve the technique.
therapy uses x-rays to kill cancer cells that might remain
after an operation or to shrink large tumors before an operation
so that they can be removed surgically. The object of radiation
therapy is to damage the tumor as much as possible without
harming surrounding tissues. Radiation may be administered
in the following ways:
WHAT IS RADIATION TREATMENT FOR RECTAL CANCER?
imaging techniques providing 3-dimensional pictures of the
cancerous area are allowing precise targeting of radiation
to the tumor.
Externally by an x-ray machine (external beam radiation).
By passing radioactive pellets through thin plastic tubes
inserted into the intestine.
By implanting tiny radiation seeds directly into the tumor
radiation treatment combined with chemotherapy is common practice
for patients with rectal cancer in Stages II and III. Such
patients are at risk of recurrence both at the site of their
original tumor and elsewhere in the body. There also can be
significant long term side effects to therapy. Nevertheless,
the combination is still considered standard of care to administer
5-FU and radiation therapy to stage II and III rectal cancer
patients after surgery.
Postoperative Radiation with Chemotherapy for Rectal Cancer
procedure in the United States is to apply radiation after
surgery. Preoperative chemotherapy and radiation, however,
are sometimes used to preserve sphincter-muscle function and
reduce the chance that a patient will require a colostomy.
Furthermore, some studies suggest that the use of radiation
before surgery may produce better survival and recurrence
rates, although the benefits appear to be small. Studies comparing
preoperative and postoperative chemotherapy and radiation
are currently underway.
therapy is also being used during surgery (called intra-operative
radiotherapy), which allows the surgeon to move healthy tissue
out of the path of the radiation beam.
Intra-Operative Radiotherapy (IORT)
side effects of radiation include:
Side effects of Radiation Therapy
complications may include the following:
skin irritation around the anus,
bowel movement problems.
hip and pelvic fractures,
increased risk for bowel obstruction.
Society of Clinical Oncology (ASCO) sets guidelines for follow-up
testing to detect recurring cancer after treatment has been
completed. These ASCO guidelines may not apply to particular
patients. Although they are based on the best available evidence,
rigorous studies are still needed to determine which tests
can best cost-effectively detect recurrence at its earliest
HOW SHOULD THE PATIENT BE MONITORED AFTER TREATMENT?
patients should have a physical examination every three to
six months for the first three years, and colonoscopy every
three to four years. A 1999 study however, suggested that
more frequent colonoscopies may be needed.
Physical Examination and Colonoscopy
[ see Carcinoembryonic Antigen (CEA) above]
should be measured every two to three months after surgery
for two years in Stage II or III patients, in whom liver surgery
for development of metastasis might be indicated. An elevated
CEA level, confirmed by retesting, warrants further evaluation
for return of metastatic disease. It should be noted that
almost a third of all recurring cancers do not produce abnormal
imaging technique called an fluorodeoxyglucose positron emission
tomography (FDG-PET) scan is now approved by Medicare to look
for recurrent or metastasized colorectal cancer in the setting
of an elevated CEA. This test is proving to be very sensitive
in detecting diseased areas.
to be no additional benefit for anyone from routine follow-up
liver function tests, fecal occult blood tests (FOBT), or
computed tomography (CT) scans. There is some debate about
whether chest x-rays should be administered annually; they
appear to detect recurring cancers but not early enough to
be very helpful for the great majority of patients.
WHAT ARE THE TREATMENT OPTIONS FOR COLORECTAL CANCER THAT
HAS SPREAD TO THE LIVER?
has spread, surgery to remove or bypass obstructions in the
intestine may be performed. In these circumstances, surgery
is considered palliative in that it may improve symptoms but
will not lead to cure. In rare cases, metastatic colon cancer
may be cured with surgical removal of tumors in areas to which
the cancer has spread, such as the liver, ovaries, and lung.
The liver is the most common site of spread. Only selected
patients may be eligible for such surgery, but in such patients
five year survival has been 25% and may be higher.
have attempted to target inoperable liver tumors using chemotherapy
administered with implanted pumps. It is possible to shrink
swollen, painful livers this way, but to date it is not clear
whether survival rates are improved.
Chemotherapy for Liver Cancer
techniques used to destroy liver tumors include:
cryosurgery (freezing the cancer tissue),
embolization (reducing blood flow to the tumor), and
Cancer Society, 1599 Clifton Road, NE, Atlanta, GA 30329.
WHERE ELSE CAN HELP BE FOUND FOR COLON AND RECTAL CANCERS?
Call (800-ACS-2345) or (404-320-3333) or (https://www.cancer.org)
In addition to offering information, the ACS has a number
of educational programs and informational materials. Call
the American Cancer Society for local chapters of the American
National Cancer Institute.
The NCI has help line open during working hours (call 800-4-CANCER)
or (800-422-6237) or (https://cis.nci.nih.gov/).
The NCI offers free information on all aspects of cancer.
The following site lists clinical trials (https://cis.nci.nih.gov/resources/clinical.html)
United Ostomy Association, 36 Executive Park, Suite 120, Irvine,
Call (800-826-0826) or (714-660-8624).
This organization refers people to local support group chapters.
They offer many free publications about ostomy care and management
and have also a subscription to bimonthly magazine Ostomy
American Institute for Cancer Research (AICR), American Institute
for Cancer Research, 1759 R Street N.W., Washington, D.C.
Call (800-843-8114) or (202-328-7744) in Washington, D.C.
For dietary recommendations: (https://www.aicr.org)
The National Colorectal Cancer Research Alliance (NCCRA)
The NCCRA is a program of the Entertainment Industry Foundation,
11132 Ventura Boulevard, Suite 401, Studio City, CA 91604-3156.
American Society of Clinical Oncology
1900 Duke Street, Suite 200, Alexandria, VA 22314.
Call (703-299-0150) or on the Internet (https://www.asco.org/)
or access its journal (https://www.jco.org/)
site for colon cancer is https://cancer.med.upenn.edu/disease/colon/.
The general site is called Oncolink and it provides excellent
links and in-depth free information. Included in their information
links for colon cancer are the National Cancer Institute's
patient and physician information sheets. They also provide
abstracts of the latest research.
American Digestive Health Foundation Call (800-668-5237)
National Comprehensive Cancer Network (https://www.nccn.org)
or call (888-909-NCCN)