According to the National Cancer Institute, individuals are considered cancer survivors from the time of diagnosis through the balance of their lives. 65.8% of cancer survivors today have passed the classic five-year survival marker, and 40% have survived 10 years or more. These survivors face myriad nutrition-related challenges, including those caused by an increased risk of cancer recurrence or the development of a second cancer. Many experience long-lasting side effects of the cancer or its treatment or they develop late effects that begin months or years after initial treatment.
Recommendations for Survivors
Research on how nutrition, physical activity, and body composition affect cancer recurrence, the development of second primary cancers, and overall survival for cancer survivors still is limited.
American Institute for Cancer Research (AICR) recommendations state that after treatment, if possible and unless otherwise advised, survivors should aim to follow the organization’s cancer prevention recommendations for diet, physical activity, and healthy weight maintenance.
Protective Eating Pattern Vegetables, fruits, whole grains, and legumes form the core of a diet that reduces the risk of cancer and heart disease. Plant foods that aren’t highly processed or refined provide a wide range of nutrients and phytochemicals that may act protectively throughout cancer development, influencing DNA repair, inflammation, cell proliferation, and cancer progression. Diets built around foods low in calorie density are recommended to avoid weight gain and support intentional weight loss.
However, neither observational nor interventional studies have demonstrated a strong link between vegetable and fruit consumption and reduced cancer recurrence or mortality. The effects of a diet high in vegetables and fruits likely are influenced by personal characteristics such as hormonal status, genetics, gut microbiota, and medical treatment as well as how the diet is implemented, including the choice and preparation of vegetables and fruits, total calorie intake, and overall diet and lifestyle quality.
Dietary recommendations from the AICR and the ACS don’t address fat consumption except to call for avoiding very high levels that contribute to obesity. The ACS recommends limiting saturated fat for heart health, noting limited data linking saturated fat with cancer risk or recurrence.
Weight and Body Composition Traditionally, nutritional care for cancer survivors has focused on preventing and treating malnutrition and on regaining lost weight, and that remains true for some of them. However, many survivors today are overweight or obese at the time of their diagnosis and remain so following treatment. This reflects both the increased prevalence of obesity and its association with cancer risk and improvements in treatment and early diagnosis reducing unplanned weight loss.
Obesity’s link to poor prognosis for cancer patients may relate to several mechanisms, including increased inflammation and elevated levels of insulin and growth factors such as IGF-1 that promote cancer cell growth. Excess body fat increases adipose production of estrogen in postmenopausal women, raising levels that promote the growth of estrogen-sensitive cancers. Obesity also is associated with the risk of developing CVD, the primary cause of death among many cancer survivors.
People at a healthy weight when they’re diagnosed with cancer may gain weight during treatment and in the years that follow. Fatigue, depression, and insomnia can lead to decreased physical activity or increased calorie intake from using food to cope with these problems, which can result in weight gain. Some chemotherapy, hormone, and steroid medications also can cause undesirable weight gain.
The ACS guidelines for cancer survivors encourage those who are overweight to achieve and maintain a healthy weight.
Physical Activity Survivorship care has changed dramatically in its emphasis on physical activity. The strongest evidence involves breast cancer survivors, including several observational studies that link greater post diagnosis physical activity with reduced all-cause mortality.
Physical activity also is associated with increased progression-free survival and reduced recurrence, cancer mortality, and all-cause mortality in colorectal and prostate cancer survivors.
Interventions promoting physical activity consistently have demonstrated improved fitness, strength, and quality of life and decreased fatigue and sleep disturbances among survivors of various cancer types.
An American College of Sports Medicine roundtable of experts developed exercise guidelines for cancer survivors, published in 2010. Based on these guidelines, survivors are encouraged to follow the federal physical activity guidelines for all Americans, though in some cases certain modifications are necessary. All survivors are advised to avoid inactivity.