| Abstract: |
Background: Observational studies suggest that higher levels of 25-hydroxyvitamin D3 (25(OH)D) are associated with areduced risk of colorectal cancer and improved survival of colorectal cancer patients. However, the influence of vitamin D statuson cancer recurrence and survival of patients with stage III colon cancer is unknown. Patients and methods: We prospectively examined the influence of post-diagnosis predicted plasma 25(OH)D on outcomeamong 1016 patients with stage III colon cancer who were enrolled in a National Cancer Institute-sponsored adjuvant therapytrial (CALGB 89803). Predicted 25(OH)D scores were computed using validated regression models. We examined the influenceof predicted 25(OH)D scores on cancer recurrence and mortality (disease-free survival; DFS) using Cox proportional hazards. Results: Patients in the highest quintile of predicted 25(OH)D score had an adjusted hazard ratio (HR) for colon cancerrecurrence or mortality (DFS) of 0.62 (95% confidence interval [CI], 0.44-0.86), compared with those in the lowest quintile(Ptrend=0.005). Higher predicted 25(OH)D score was also associated with a significant improvement in recurrence-free survivaland overall survival (Ptrend=0.01 and 0.0004, respectively). The benefit associated with higher predicted 25(OH)D score appearedconsistent across predictors of cancer outcome and strata of molecular tumor characteristics, including microsatellite instabilityand KRAS, BRAF, PIK3CA, and TP53 mutation status. Conclusion: Higher predicted 25(OH)D levels after a diagnosis of stage III colon cancer may be associated with decreased recurrenceand improved survival. Clinical trials assessing the benefit of vitamin D supplementation in the adjuvant setting are warranted. © The Author 2017. Published by Oxford University Press on behalf of the European Society for Medical Oncology. All rights reserved. |
