Apr 26, 2012 6:19 PM
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.
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.
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.
Among the specific findings:
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.