Positive affect and fatigue as predictors of anti-inflammatory IL-10 concentrations among colorectal cancer patients during adjuvant chemotherapy

Objectives: (1) To examine the relationships of positive and negative affect and symptoms of depression, anxiety, and fatigue at baseline with the anti-inflammatory cytokine IL-10 concentrations in serum at three points in colorectal cancer patients; and (2) to assess the relationship between these factors and disease recurrence or mortality after a median follow-up of 24 months. Methods: In a prospective trial, 92 stage II or III colorectal cancer patients scheduled to receive standard chemotherapy were enrolled. Blood samples were collected prior to start of chemotherapy onset (T0), 3 months later (T1), and upon chemotherapy completion (T2). Results: IL-10 concentrations were similar across the time points. Linear mixed-effects model analysis showed that controlling for confounders, higher positive affect and lower fatigue pretreatment (T0) predicted IL-10 concentrations across the time points (estimate = 0.18, SE = 0.08, 95% CI = 0.03, 0.34, p < .04 and estimate = −0.25, SE = 0.12, 95% CI = −0.50, 0.01, p < .04, respectively). Depression at T0 significantly predicted higher disease recurrence and mortality (estimate = 0.17, SE = 0.08, adjusted OR = 1.18, 95% CI = 1.02, 1.38, p = .03). Conclusions: We report on associations not previously assessed between positive affect and fatigue and the anti-inflammatory cytokine IL-10. Results add to previous findings suggesting that positive affect and fatigue could have a role in anti-inflammatory cytokine dysregulation.