The American Cancer Society (ACS) issued a report discussing optimal nutrition and physical activity issues during the phases of cancer treatment and recovery, living after recovery from treatment, and living with advanced cancer. The full report appeared in the September/October issue of CA: A Cancer Journal for Clinicians (http://CAonline.amcancersoc.org/cgi/content/full/53/5/268).
Nutrition and Physical Activity Across Stages of Cancer Survivorship
The spectrum of cancer survival includes treatment and recovery, living after recovery, and living with advanced cancer. Each of these stages has different requirements and challenges in terms of nutrition and physical activity that are influenced by the primary site of cancer and therapeutic methods.
TREATMENT AND RECOVERY
Surgery, chemotherapy, and radiation therapy can affect a cancer patient's digestion, absorption, and use of food, which in turn can cause unintentional weight loss or gain, and loss of muscle mass. Common cancer symptoms and toxic effects of cancer treatments include anorexia, weight change, fatigue, nausea, vomiting, pain, changes in taste or smell, and changes in bowel habits.
The most important nutritional goal for cancer survivors at risk of unintentional weight loss (e.g., persons who are already undernourished or persons who receive directed treatment to the alimentary tract) during active cancer treatment is maintaining energy balance or preventing weight loss. If the patient is experiencing early satiety or reduced appetite, eating smaller, more frequent meals may increase food intake. Nutritious snacks or nutrient-dense drinks may be appropriate for persons who cannot meet their nutritional needs through regular diet alone.
The use of dietary vitamin and mineral supplements during cancer treatment remains controversial. Until further evidence is available that suggests more benefit than harm, the authors of the report recommend that cancer survivors receiving chemotherapy or radiotherapy avoid exceeding the tolerable upper limits of the Dietary References Intake for antioxidant vitamins such as vitamins C and E.
It is unknown whether exercise during cancer treatment has any effect on treatment efficacy. Deciding when to initiate physical activity should be based on the patient's condition and personal preferences. Patients receiving radiation therapy and chemotherapy should alter their program or begin exercise at a lower intensity and progress at a slower pace compared with persons who are not receiving cancer treatment. Patients who were exercising regularly before diagnosis should try to maintain levels of activity as much as possible. Patients who were sedentary before diagnosis should adopt low-intensity activities such as short, slow walks and stretching. Special attention should be given to balance and reducing the risk of falls and injuries in older persons and those with significant impairments. If the disease or treatment requires extended periods of bed rest, then reduced endurance, reduced fitness, and decreased muscle strength should be expected. Physical therapy is recommended for these patients.
LIVING AFTER RECOVERY FROM TREATMENT
Most cancer survivors are free of disease or stable after the initial diagnosis and treatment. During this period, it is important to set and achieve lifelong goals for appropriate weight, healthy diet, and a physically active lifestyle. The report recommends that following the ACS guidelines on diet, nutrition, physical activity, and cancer prevention may help reduce the risk of cancer recurrence (Table 1).
LIVING WITH ADVANCED CANCER
For patients living with advanced cancer, nutrition and physical activity are vital to establishing and maintaining well-being and quality of life. Many of these patients may need to adapt food choices and eating patterns to meet nutritional needs and to manage symptoms and adverse effects such as pain, constipation, and loss of appetite. There is some evidence that medications, such as megestrol acetate, may enhance appetite in these patients. The use of nonsteroidal anti-inflammatory drugs or omega-3 fatty acid oral supplements may stabilize or improve nutritional status, functional status, and body weight.
Physical activity may help increase appetite and relieve constipation. The ACS report recommends that the use of tube feedings and total parenteral nutrition be individualized, with clear recognition of the associated risks for complications.
|Eat a variety of healthful foods, with an emphasis on plant sources.|
|Eat five or more servings of a variety of vegetables and fruits each day.|
|Choose whole grains instead of processed (refined) grains and sugars.|
|Limit consumption of red meats, especially those that are high in fat and processed.|
|Choose foods that help maintain a healthful weight.|
|Adopt a physically active lifestyle.|
|Adults: Engage in at least moderate activity for at least 30 minutes on five or more days of the week; 45 minutes or more of moderate to vigorous activity on five or more days per week may further enhance reductions in the risk for breast and colon cancer.|
|Children and adolescents: Engage in at least 60 minutes per day of moderate to vigorous physical activity at least five days per week.|
|Maintain a healthy weight throughout life.|
|Balance caloric intake with physical activity.|
|Lose weight if currently overweight or obese.|
|Limit consumption of alcoholic beverages.|
Issues by Selected Cancer Sites
The association between obesity and adverse breast cancer outcome is substantial and may vary by stage and diagnosis. Women who are overweight should pursue modest weight loss (1 to 2 lb [0.45 to 0.91 kg] per week) provided it is approved by the treating oncologist, monitored closely, and does not interfere with treatment. These patients should eat a diet that emphasizes fruits and vegetables, low amounts of saturated fats, soy foods in moderation, and moderate or no alcohol intake. Most importantly, these women should try to maintain a healthy weight through appropriate diet and regular physical activity.
Studies have found that the risk of colorectal cancer is associated with diets high in red meat and saturated fats and low in fruits and vegetables; sedentary lifestyles and obesity; and possibly excess alcohol consumption. Survivors of colorectal cancer should maintain a healthy weight, participate in regular physical activity, and eat a well-balanced diet consistent with guidelines for prevention of cancer and heart disease. Patients with chronic bowel problems or surgery that affects normal absorption of nutrients should be referred to a registered dietitian.
Lung cancer mainly is caused by cigarette smoking, but diets low in fruits and vegetables are associated with increased risk. For patients who are living with lung cancer, nutrition and physical activity recommendations should be based on individual needs. Adjusting food intake and engaging in physical activity will help achieve a healthy weight. A well-balanced diet will ensure that micronutrient needs are met. In some patients, a multivitamin-mineral supplement may be necessary.
The same dietary factors that are associated with reduced incidence of prostate cancer also may reduce the rate of prostate cancer progression, although good evidence from clinical trials is lacking. A diet high in saturated fat (especially foods from animal sources) has been associated with an increased risk of prostate cancer. Men who have been diagnosed with prostate cancer should eat a diet high in fruits and vegetables and low in saturated fat, and remain physically active. Although there is limited evidence relating these recommendations to prostate cancer recurrence, there likely are other benefits such as decreasing cardiovascular disease risk.
|Breast cancer||Colorectal cancer||Lung cancer||Prostate cancer|
|Cancer recurrence||Overall survival*||Quality of life||Cancer recurrence||Overall survival*||Quality of life||Cancer recurrence||Overall survival*||Quality of life||Cancer recurrence||Overall survival*||Quality of life|
|Omega-3 fatty acid||B||B||B||B||B||B||B||A3||B||B||B||B|
The report stresses that health care providers and cancer survivors should consider the nutritional and physical activity issues discussed in this report within the context of the individual cancer survivor's overall medical and health situation. They add that this report is not implying that nutrition and physical activity are more important than other health factors. The strength of current scientific evidence linking major components of diet to common cancer sites is summarized in Table 2.