The American Cancer Society Nutrition and Physical Activity Guidelines for Cancer Survivors recommend that survivors engage in regular physical activity and exercise for at least 150 minutes a week, including strength training twice a week.
The guidelines also recommend that survivors should follow diets rich in vegetables, fruits, and whole (instead of refined) grains, and limit their consumption of red and processed meats.
According to Erin Van Blarigan, ScD, Assistant Professor at the University of California, San Francisco, many cancer survivors do not meet these recommendations for diet and exercise because of many barriers, such as side effects, fatigue, conflicting advice from the care team, or the wish to simply “move on” and get back to so-called normal life.
“Emerging data do suggest that people who follow these guidelines have longer survival,” Dr. Van Blarigan said at the 2018 Cancer Survivorship Symposium.
Physical Activity Improves Survival
Research has consistently demonstrated that exercise during and after cancer treatment reduces patients’ symptoms and improves quality of life.
Studies with more than 2,600 women with breast cancer who engaged in exercise during cancer therapy showed that exercise improved the patients’ physical fitness, quality of life, cognitive function, and muscle strength, and reduced their fatigue and mood disturbances, according to Dr. Van Blarigan.
A study of more than 500 women with colon cancer showed that patients who increased their physical activity after a colon cancer diagnosis had half the risk of death compared with patients who did not change their physical activity habits.
Diet and Survival
However, the association between nutrition and survival for patients with cancer or cancer survivors is not so clear, according to Dr. Van Blarigan.
Several studies analyzed 2 diets in patients with cancer—(1) the Prudent diet, which is rich in vegetables, fruits, legumes, fish, poultry, and whole grains, and (2) the Western diet, which includes red meat, processed meat, high-fat dairy, refined grains, snacks, sweets, and desserts.
One study of about 2,000 women with early-stage breast cancer showed that women who consistently followed the Prudent diet (which is rich in vegetables, fruits, fish, and poultry) had a 43% lower risk of death than those who did not follow this diet.
In another study of more than 1,000 patients with stage III colon cancer, those who followed the Western diet (that includes red and processed meat) were more than twice as likely to die than patients who followed a healthier diet.
In addition, many studies suggest that diet after a cancer diagnosis plays a bigger role in terms of cancer recurrence (coming back) and survival; however, it is not easy to separate the effects of individual foods from the overall dietary patterns or other lifestyle factors (such as physical activity or weight) to know what has the greater impact, according to Dr. Van Blarigan.
Nonetheless, a healthy diet can help to reduce the risk for other medical conditions (such as heart disease or diabetes) and potentially prevent cancer progression and recurrence.
To Supplement or Not to Supplement?
The guidelines also recommend that cancer survivors should aim to meet their nutrition needs through a well-balanced diet rather than supplements, but dietary supplements can be used when necessary.
“But it’s important to recognize that many dietary supplements contain levels that exceed amounts found in food or recommended for optimal health, so they should be used carefully,” Dr. Van Blarigan emphasized.
The evidence on taking supplements after a cancer diagnosis suggests it could be beneficial or harmful, depending on whether the person has a deficiency in a particular nutrient.
“The story of vitamin D and colorectal cancer is a promising one,” Dr. Van Blarigan said. In a study called SUNSHINE, patients with metastatic colorectal cancer who took high doses of vitamin D had a longer period without cancer progression than those taking the standard dose of the vitamin. However, Dr. Van Blarigan noted, it is important to remember that vitamin D deficiency is common, especially in New England, where the study was conducted, so those patients might have been deficient in vitamin D and therefore benefited from supplements.
Ask Your Care Team
Remember that dietary supplements during cancer treatment can do harm. For example, in a study of patients with head and neck cancer undergoing radiation therapy, patients who were smokers and took antioxidant supplements during radiation therapy had a 2-fold greater risk of cancer recurrence and death than those who did not take the supplements, but taking the supplements had no effect on patients who were nonsmokers.
“Work with your doctor to determine if you actually need supplementation for an established deficiency or condition,” Dr. Van Blarigan advised.
Join a YMCA Program
The LIVESTRONG Foundation and the YMCA run 12-week group exercise programs, which are offered at many YMCA facilities throughout the country. These programs have been shown to be effective at improving heart health and general quality of life, as well as reducing cancer-related fatigue.
“There is hard evidence to show that participating in these programs can improve outcomes,” Dr. Van Blarigan said.
Digital health interventions that use wearable physical activity trackers, such as the Fitbit, can also help people to become physically active, by providing reminders and motivational messages, strategies, and tips that help people be more active physically.