Physical Activity Reduces Colorectal Cancer Morbidity and Mortality

It is not yet known how exercise affects CRC, and cancer in general. Dr. Meyerhardt believes that the potential benefits may be partially attributable to the ability of exercise to modulate insulin metabolism. He noted that elevated insulin and insulin-like growth factors are predictive of increased CRC morbidity and mortality, as is elevation of C-peptide, another marker of insulin resistance.

Insulin resistance and all the metabolic changes that go with it may be a common factor between obesity and colorectal cancer. While not all studies have shown a direct correlation, there are data to suggest that a BMI over 30 kg/m2confers a 25% increase in risk of colorectal cancer recurrence and death.

‘With the rising incidence of obesity in the U.S., we are seeing more obese colorectal cancer patients," said Dr. Meyerhardt. "It used to be that only about 5% of colorectal cancer patients were obese. Now it’s roughly 10%."

He concluded that while there are many unanswered questions, there’s little harm and much potential good in recommending moderate regular physical activity for patients who have undergone surgery and adjuvant chemotherapy for colorectal cancer. Benefits increase if patients can shift toward a low-fat diet rich in vegetables and low in red meat and processed foods, he added.