For cancer survivors, exercising and maintaining a healthy weight are important factors in preventing malignancy's return, at least for some forms of the disease.

That's the conclusion of an American Cancer Society report that updates nutrition and physical activity recommendations for cancer survivors during and after treatment.

Among the points contained in the report:

• For some kinds of cancer, just 1 to 3 hours a week of exercise can lower the risk of cancer recurrence and death, as well as death from all causes. Exercise has also been shown to improve fitness, fatigue, and several other quality of life aspects in cancer survivors.
• While a vegetarian diet can help health in some ways, there's no direct evidence that this kind of diet can prevent cancer recurrence. Survivors who eat a vegetarian diet should ensure that they're getting an adequate intake of nutrients.
• A standard multivitamin and mineral supplement in amounts equivalent to 100 percent of the Daily Value can help cancer survivors meet their nutrient needs when it's difficult for them to eat a healthy diet. However, some supplements -- such as those with high levels of folic acid or antioxidants -- may be harmful during cancer treatment.
• Food safety is especially important for cancer survivors, particularly during treatment that involves immunosuppression.
• Alcohol can affect the risk for new primary cancers in certain areas of the body.

The report is published in the November/December issue of CA: A Cancer Journal for Clinicians.