Colorectal cancer is the third most common cancer and second leading cause of cancer-related death worldwide. Standard management of stage III or high-risk stage II colon cancer includes surgery followed by 3 to 6 months of treatments. Despite these treatments, recurrent disease develops in 20 to 40% of the patients. Moreover, surgery and adjuvant chemotherapy for colon cancer cause side effects that undermine quality of life and reduce physical functioning. Interventions that improve both survival and quality of life in this patient population are needed.
Preclinical studies have shown that exercise can reduce the growth of cancer, including colon cancer. In addition, observational studies have shown that patients with colorectal cancer who perform an increased amount of recreational physical activity after treatment have a lower risk of cancer recurrence and death, including those with stage III colon cancer.
Possible mechanisms for these associations include the effects of exercise on metabolic growth factors, inflammation, and immune function. Although these findings are suggestive of an exercise-related survival benefit, results are inconclusive, given the methodologic limitations of observational designs.
To address this research gap, the Canadian Cancer Trials Group (CCTG) launched the CO.21 Colon Health and Lifelong Exercise Change (CHALLENGE) trial, a phase 3 randomized trial comparing the effects of providing health education materials alone or such materials plus a 3-year structured exercise program in patients with colon cancer who had completed adjuvant chemotherapy.
