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.