Inflammation, physical activity, and disease-free survival in stage III colon cancer: Cancer and Leukemia Group B-Southwest Oncology Group 80702 (Alliance).

BACKGROUND: Inflammation and insufficient physical inactivity contribute to individual-level risk of disease recurrence and death in stage III colon cancer. The extent to which increased inflammatory risk can be offset by sufficient physical activity remains unknown. METHODS: This cohort study was nested within the Cancer and Leukemia Group B (now part of the Alliance for Clinical Trials in Oncology) and Southwest Oncology Group randomized trial. Inflammatory burden was quantified by high-sensitivity C-reactive protein, interleukin-6, and soluble tumor necrosis factor-α receptor 2 after recovery from tumor resection. Physical activity was measured during and after postoperative chemotherapy. The primary endpoint was disease-free survival. RESULTS: The 3-year disease-free survival rate was 88.4% among patients with low inflammation and sufficient physical activity (referent group for all comparisons), 84.9% with low inflammation and insufficient physical activity (absolute risk difference = -3.5 percentage points, 95% confidence interval [CI] = -11.3 to 4.3; P = .38), 78.0% with intermediate inflammation and insufficient physical activity (absolute risk difference = -10.4 percentage points, 95% CI = -17.4 to -3.3; P = .007), and 79.7% with high inflammation and insufficient physical activity (absolute risk difference = -8.7 percentage points, 95% CI = -15.7 to -1.6; P = .022). In contrast, the 3-year disease-free survival rate was 87.3% among patients with intermediate inflammation and sufficient physical activity (absolute risk difference = -1.1 percentage points, 95% CI = -7.5 to 5.3; P = .74) and 84.4% with high inflammation and sufficient physical activity (absolute risk difference = -4.0 percentage points, 95% CI = -12.3 to 4.3; P = .34). CONCLUSION: In this observational study of stage III colon cancer patients, physical activity was associated with improved disease-free survival despite high inflammation. Patients with intermediate or high inflammation who were physically active had disease-free survival rates that were not statistically significantly different from those with low inflammation.