Diet, Lifestyle and Colon Cancer Survival

I often lecture about how diet and lifestyle choices affect not only cancer risk but also cancer survival. Now new research proving that fact is being featured at the annual meeting of the American Society of Clinical Oncology starting this week in Chicago.

A retrospective analysis of a large study supported by the National Institutes of Health showed that colon cancer survival improved significantly in patients who followed a healthy diet and lifestyle. According to study leader Dr. Erin L. Van Blarigan, of the University of California San Francisco, colon cancer patients who maintained a healthy body weight, engaged in regular physical activity, and ate a diet rich in vegetables and whole grains and low in red meat and processed meat had longer disease-free periods and longer overall survival than patients who did not.

During a 7-10 year follow-up period, the former group had a 42% lower risk of cancer recurrence or death as compared with patients who did not follow the 2012 American Cancer Society guidelines for nutrition and physical activity for cancer survivors. When moderation in alcohol consumption was included in the analysis, the likelihood of death or cancer recurrence was 51% lower.

The findings came from analysis of a study of 992 patients with stage III colon cancer who participated in a clinical trial between 1999 and 2001. All patients had surgery and were randomized to receive one of two types of chemotherapy. The drug trial showed no difference in overall survival between the treatment groups. However, Van Blarigan and colleagues had the patients complete questionnaires relating to diet and lifestyle, followed them for 7-10 years, and found huge differences in survival.

The study participants were assigned scores for weight (normal to obese), physical activity (rare to frequent), and alcohol consumption (light to heavy). Highest scores were earned for consuming at least 2 ½ cups of fruits and vegetables a day, eating whole grains instead of white flour and rice, keeping a healthy body weight, exercising at least half an hour a day, and drinking only moderately. Considering only the weight and physical activity recommendations, the results showed that patients with a total score of 5 to 6 had a 42% lower risk of death or cancer recurrence than did the patients with scores of 0 to 1. When alcohol recommendations were included, patients with scores of 6 to 8 had a 51% lower risk of death and 36% lower risk of cancer recurrence compared with patients who had scores of 0 to 2.

In general, the more people followed the lifestyle recommendations, the less likely they were to have their cancer come back and the less likely they were to die. Although 20% of those who followed the guidelines did die during the seven-year follow-up period, in the group which did not adhere to the guidelines, 35% – nearly double — died.

In related research, a multi-institutional study led by Dr. Temidayo Fadelu of Dana-Farber Cancer Institute in Boston looked at 826 patients with stage III colon cancer and found that regular consumption of tree nuts (not peanuts) was associated with a significant reduction in disease recurrence and mortality. Patients who consumed two or more 1-oz servings of nuts weekly [we specify unroasted and unsalted] had a 42% lower risk of colon cancer recurrence and a 57% lower risk of death during the follow-up period.

Conjecturing as to exactly how diet and lifestyle choices influence cancer survival, the researchers surmised that healthier eating and exercise may affect cancer growth by lowering insulin resistance, improving bowel function through higher fiber, reducing cancer-promoting inflammation, or altering the microbiome — the balance of microbes in the body.

Conclusion

According to the American Cancer Society, colorectal cancer is the third most commonly diagnosed cancer in Americans and the second leading cause of cancer death in the U.S. More than 95,000 people will be diagnosed with colon cancer this year and nearly 40,000 will be diagnosed with rectal cancer. The two cancers will kill more than 50,000 people this year. Healthy diet and lifestyle changes can improve recurrence and survival rates by at least 50%.

As NBC News writer Maggie Fox wrote in her article “Colon Cancer Survivors Live Longer with Healthy Habits” (nbcnews.com), “There’s a straightforward way to live longer after being diagnosed with advanced cancer and it doesn’t involve chemotherapy or surgery. It’s just eating right and exercising more.” Added Dr. Van Blarigan, “Everyone seems to know that these behaviors are healthy and that people who do these things are going to live longer [but] the magnitude of the benefit was surprising.” And while the researchers studied only colon cancer patients, they say their findings are likely to apply to many types of cancer survivors. That is certainly what we have observed at BeatCancer.org.

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