ASCO: Healthy Lifestyle Adds to Colon Cancer Survival

CHICAGO -- Colon cancer survival improved significantly in patients who followed lifestyle recommendations related to diet, physical activity, and alcohol intake, a retrospective analysis of a large cohort study showed.

Patients who maintained a healthy body weight and engaged in regular physical activity had a 42% lower risk of death or cancer recurrence during follow-up 7 to 10 years, compared with patients who did not follow lifestyle recommendations developed by the American Cancer Society (ACS). When moderation in alcohol consumption was included in the analysis, the risk of death or cancer recurrence was 51% lower in the patients who followed the recommendations.

"Colon cancer patients who had a healthy body weight, engaged in regular physical activity ... and drank small to moderate amounts of alcohol had longer disease-free and overall survival than patients who did not," Erin L. Van Blarigan, ScD, of the University of California San Francisco said during a press briefing prior to the American Society of Clinical Oncology (ASCO) annual meeting, which begins here June 2.

The researchers have begun clinical trials to evaluate the feasibility and potential utility of using digital lifestyle intervention (such as Fitbit) as aids to follow-up care for patients with colorectal cancer.

"If our interventions are acceptable and useful to patients, we will test their impact on the risk of cancer recurrence and mortality in future studies," said Van Blarigan.

A related presentation showed that regular consumption of tree nuts also was associated with a lower risk of colon cancer recurrence and improved overall survival, emphasizing dietary factors as a potential contributor to outcomes in colon cancer.

Noting that the findings came from a randomized trial comparing two types of chemotherapy for colon cancer, said ASCO President Daniel Hayes, MD, who cautioned against interpreting the results as meaning that lifestyle changes can replace cancer treatment.

"The odds of surviving colon cancer, if it is not metastatic, are quite high these days, thanks to lots of hard work and a number of trials done over the last 30 years showing that adequate surgery and adjuvant chemotherapy improve survival," said Hayes, of the University of Michigan in Ann Arbor. "These two abstracts really tell us that you have a pretty good chance of surviving if you have colon cancer and that healthy people live healthier."

"Nobody wants to undergo chemotherapy. We understand that, but chemotherapy clearly saves lives," Hayes added. "People should not interpret these two abstracts as suggesting that if you live a healthy lifestyle and you eat tree nuts, you don't need to take the chemotherapy that your oncologist would recommend. That's a very dangerous interpretation."

The ACS published recommendations for nutrition and physical activity for cancer survivors in 2012. Whether adherence to the guidelines improved survival or other outcomes among patients with cancer remained unclear. Van Blarigan reported findings from an analysis designed to inform the issue.

The analysis involved data from a prospective cohort of 992 patients with stage III colon cancer who participated in the CALBG 89803 trial conducted during 1999 to 2001. All patients had surgery and were randomized to receive one of two types of adjuvant chemotherapy. As previously reported, the trial showed no difference in disease-free or overall survival (OS) between the treatment groups.

Van Blarigan retrospectively applied the ACS guidelines to 992 participants in the trial, who were followed through 2009 (median follow-up 7 years). The patients completed lifestyle questionnaires during treatment with chemotherapy and 6 months afterward. Subsequently, 378 patients died or had recurrent colon cancer.

The analysis focused on recommendations pertaining to weight, physical activity, and alcohol consumption. The guideline also addressed diet, which was not included in the analysis. The guideline did not specifically address alcohol consumption, but it was addressed in the text, said Van Blarigan.

The 992 study participants were assigned scores of 0 to 2 for weight (normal to obese), increasing amounts of physical activity, and alcohol consumption (light/moderate to heavy). A higher score reflected better adherence to the recommendations.

Considering only the weight and physical activity recommendations, the results showed that patients with a total score of 5 to 6 (n=91) had a 42% lower risk of death or cancer recurrence during follow-up than did the 262 patients with scores of 0 to 1. The analysis showed a significant trend toward improved outcomes with higher lifestyle scores (P=0.01).

When alcohol recommendations were included, patients with scores of 6 to 8 (n=162) had 51% lower risk of death and 36% lower risk of cancer recurrence compared with 187 patients who had scores of 0 to 2. Across the range of scores, the analysis showed a significant association between higher lifestyle scores and better outcomes (P=0.002).

The analysis of tree nut consumption included 826 patients from the 89803 clinical trial. Interest in evaluating tree nut consumption as a potential contributor to outcome in the trial came from previous studies showing positive associations between regular consumption of nuts and OS in cardiovascular disease and cancer, as well as a reduced risk of type 2 diabetes, metabolic syndrome, and insulin resistance, said Temidayo Fadelu, MD, of Dana-Farber Cancer Institute in Boston.

The results showed that patients who consumed two or more 1-oz servings of nuts weekly had a 42% lower risk of cancer recurrence and a 57% lower risk of death from any cause during the follow-up period.

"The associations were limited to tree-nut intake and were not significant for consumption of peanuts or peanut butter," said Fadelu. "The biologic mechanism is unknown but is likely related to the effect of nuts on insulin resistance."

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