Chicago, IL—Healthcare practitioners can now tell their patients with stage III colon cancer that eating tree nuts (eg, walnuts, almonds, hazelnuts, cashews, and pecans) and maintaining a healthy lifestyle can improve their chances of overall survival as well as recurrence-free survival. Two subanalyses of the CALGB 89803 (now Alliance) study provided strong evidence supporting the survival benefits of these nondrug interventions. Both analyses were presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting, and were featured in a premeeting press cast.
CALGB 89803 was a large, prospective trial that compared 2 adjuvant chemotherapy regimens in patients with stage III colon cancer between 1999 and 2001. Embedded in the study was a self-administered questionnaire designed to capture diet and lifestyle factors prospectively during adjuvant therapy and again 6 months later.
“These studies clearly show that in addition to good, standard cancer treatment, which has reduced mortality due to colorectal cancer substantially, what patients eat, drink, and do afterward can make a difference,” stated ASCO President Daniel Hayes, MD, FACP, FASCO, Professor, University of Michigan School of Medicine, Ann Arbor. He also emphasized that healthy lifestyle choices do not replace standard cancer care.
Tree Nut Consumption
The analysis of nut consumption was based on a prospective, observational study of 826 patients, with disease-free survival as the primary end point. Patients who consumed ≥2 servings of tree nuts per week had a 42% reduced risk for recurrence, and a 57% reduced risk for death compared with patients who did not (P = .03 and P = .01, respectively).
In patients who reported a consumption of ≥1 weekly servings of tree nuts, the risk for recurrence was reduced by 46% (P = .04), and risk for death was reduced by 53% (P = .04) compared with patients who did not. The benefit did not extend to the consumption of peanuts or soy nuts, which have different metabolic compositions compared with tree nuts.
“Patients with advanced disease who benefit from chemotherapy frequently ask what else they can do to reduce their chances of disease recurrence or death, and our study is an important contribution to the idea that modifying diet and physical activity may be beneficial,” said lead investigator Temidayo Fadelu, MD, Clinical Fellow in Medicine, Brigham and Women’s Hospital, Dana-Farber Cancer Institute, Boston, MA.
A separate subanalysis of 992 patients with stage III colon cancer enrolled in CALGB 89803 found that those who had the highest lifestyle scores enjoyed a 42% reduced risk for death (P = .01) and a trend toward reduced risk for recurrence (P = .03) compared with those reporting the lowest lifestyle scores. Lifestyle scores were calculated according to adherence to the American Cancer Society nutrition and physical activity guidelines. Components of the American Cancer Society guidelines were body mass index, physical activity, and dietary intake of vegetables, fruits, whole grains, and red or processed meats. Scores ranged from 0 to 6, with higher scores reflecting healthier behaviors. A score of 5 to 6 was considered the highest, and 0 to 1 the lowest.
At a median follow-up of 7 years, 91 survivors had the highest healthy lifestyle scores (5-6 points) compared with 262 survivors with the lowest healthy lifestyle scores (0-1 points).
Alcohol consumption was also protective if it was low to moderate (limited to 1 drink per day for women and 2 drinks per day for men). When alcohol was included in the score, those with the highest scores had a 51% reduced risk for death (P = .002) and a 36% reduced risk for recurrence (P = .05) compared with those with the lowest scores.
“Colon cancer patients with a healthy body weight who engaged in physical activity, ate a diet high in whole grains, vegetables, and fruits, and low in red or processed meats, and had moderate alcohol intake had longer recurrence-free and overall survival than patients who did not engage in these behaviors,” said lead investigator Erin Van Blarigan, ScD, Assistant Professor, Departments of Epidemiology and Biostatistics, and Urology, Helen Diller Family Comprehensive Cancer Center, University of California San Francisco.