In guidelines released today, the group affirmed the importance of following a healthy lifestyle following a cancer diagnosis.
The Society has long recommended these measures to prevent certain cancers, and officials say the evidence now shows that healthy lifestyle has a direct impact on cancer recurrence and survival.
Healthy Lifestyle = Better Cancer Outcomes
Nearly 12 million Americans, or 1 in 25 people, are cancer survivors, meaning that they have been diagnosed with the disease at some point in their lives.
For some time, proper nutrition and physical activity have been thought to play a role in surviving cancer. But this is the first time the American Cancer Society has issued formal guidelines for survivors, says Society Director of Nutrition and Physical Activity Colleen Doyle, MS, RD.
"Since our last report was published in 2006, more than 100 studies examining weight control, diet, and physical activity have been published," she tells WebMD.
The studies overwhelmingly suggest that eating a mostly plant-based diet, exercising regularly, and avoiding obesity can lower cancer recurrence risk and improve survival, she says.
After Surgery, Patient Becomes a Believer
Breast cancer survivor Crystal King worked out some, but not every day, and she was no fan of vegetables before her cancer diagnosis nearly a decade ago when she was in her mid-20s.
After her cancer surgery, King joined a gym, started running, and learned to love the healthy foods she previously only tolerated.
"My doctors believed these things would help reduce the chances that my cancer would come back, but at that point they couldn't really prove it," King tells WebMD.
Although most of the lifestyle studies have been in survivors of breast, prostate, and colorectal cancer, Doyle says it is likely that healthy lifestyle choices benefit survivors of other cancers as well.
The new report summarizes the scientific evidence on the impact of diet, exercise, and weight control on cancer recurrence and cancer death.
Diet: Limit Red and Processed Meat
Among the specific findings:
- Studies in breast cancer survivors have shown that a diet high in fruits, vegetables, whole grains, poultry, and fish is associated with a lower risk of death than one that contains a high intake of processed and red meat, refined grains, sugar, and high-fat dairy products.
- Eating a healthy diet low in red and processed meat appears to protect against cancer progression, risk of recurrence, and overall survival for a variety of cancers.
- Regular exercise appears to be associated with a lower risk for recurrence and improved survival following treatment for breast, prostate, ovarian, and colorectal cancers.
- Moderate exercise during cancer treatment has been shown to improve fatigue, anxiety, and self-esteem, as well as heart health and muscle strength.
- Cancer survivors who are overweight or obese may benefit from intentional weight loss following treatment.
Supplements Not Recommended
The report recommends that cancer survivors obtain the nutrients they need from foods instead of supplements, noting that "a concern exists that supplements may do more harm than good" following the diagnosis and treatment of cancer.
Doyle says a specific concern is that certain high-dose antioxidant supplements may reduce the effectiveness of cancer treatments and promote the recurrence of some cancers.
"There is no good evidence that supplements reduce recurrence risk and increasing evidence that they may be harmful in some cases," Doyle says. "Before taking a supplement, cancer patients and survivors should definitely discuss it with someone on their health care team."
The report appears online in the American Cancer Society publication CA: A Cancer Journal for Clinicians.