Manish Shah, MD

Daniel F. Hayes, MD, FACP, FASCO

Manish Shah, MD, Director of Gastrointestinal Oncology at NewYork-Presbyterian and Weill Cornell Medicine, was impressed with the findings of the two subanalyses of CALGB 89803. 

“The study found a 46% reduction in the risk of recurrence with two servings of tree nuts a week, and that’s more than we usually get with chemotherapy. If this is real, it’s amazing,” he commented to The ASCO Post.

He noted that with the identification of molecular subtypes in colon cancer, “we used to be lumpers, and now we are splitters.” It will be even more “compelling” if nut consumption exerts a greater impact on certain subtypes than others, added Dr. Shah, as could be expected if the effect of tree nut consumption on reducing the risk of recurrence has a biologic rationale. Meanwhile, the data suggest that “eating nuts reduced risks across the board.” 

Dr. Shah acknowledged the obvious question of whether nut consumption might simply be a component of a healthier lifestyle or more common among healthier persons; this could explain the association with improved cancer outcomes. “But the study found an effect with tree nuts and specifically not with peanuts,” he emphasized. “That strengthens the idea that perhaps there is an effect of certain proteins from these particular nuts that could be altering metabolism or the microbiome, thereby leading to reductions in recurrence.” 

Support for a Healthy Lifestyle

As to the effect of a healthy lifestyle, Dr. Shah noted the study’s design was based on the scoring system developed by -McCullough et al in the Cancer Prevention Study of nearly 112,000 persons.¹ Their study showed, as did the current analysis, that the highest lifestyle scores were associated with reduction in the risk for cancer (not just colon cancer). The current study confirms this important previous work, showing that healthier lifestyles are important, said Dr. Shah. He added that the use of aspirin and statins might also reduce colon cancer recurrence risk. 

The study found a 46% reduction in risk of recurrence with two servings of tree nuts a week.… If this is real, it’s amazing.

— Manish Shah, MD

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Since these are all associations and the findings do not show cause-and-effect, one cannot be sure of the “precision” of the numbers with regard to the specific magnitude of benefit with one factor vs another, Dr. Shah cautioned. “The key thing for patients is to realize that what they do after their colon cancer diagnosis can have important effects on the risk of recurrence,” he explained. “There is a lot about disease biology that we don’t yet understand, but the data are adding up in support of a healthy lifestyle—being active, having a balanced diet—as likely to benefit patients. The downside to this approach is low, and the upside is significant.”

ASCO President Daniel F. Hayes, MD, FACP, FASCO, agreed that the 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.” He emphasized, however, that healthy lifestyle choices are no substitute for standard cancer care. ■

Disclosure: Drs. Shah and Hayes reported no conflicts of interest.

Reference

1. McCullough ML, Patel AV, Kushi LH, et al: Following cancer prevention guidelines reduces risk of cancer, cardiovascular disease, and all-cause mortality. Cancer Epidemiol Biomarkers Prev 20:1089-1097, 2011.