Serum C-reactive protein (CRP) is a sensitive marker of systemic inflammation. Since there is a well-recognized relationship between local inflammation and colorectal cancer, we aimed to evaluate whether serum CRP levels were associated with the occurrence of colorectal adenomas and serrated polyps using data from a large adenoma prevention trial. 930 participants with a history of colorectal adenomas were enrolled in a randomized trial of calcium supplementation (1200 mg/day) for the prevention of colorectal adenomas. Outcomes in this analysis are metachronous adenomas (and advanced neoplasms specifically), and serrated polyps at follow-up colonoscopy. High sensitivity CRP levels were measured 1 year following baseline colonoscopy. Multivariate analysis was performed to estimate risk ratios (RR) using Poisson regression, controlling for potential confounders. We measured serum CRP levels in 689 participants(mean CRP 3.62mg/L ± 5.72). There was no difference in CRP levels with respect to calcium vs. placebo treatment assignment (p=0.99). After adjustment for potential confounders, we found no association between CRP level and risk of recurrent adenoma or advanced lesion (Quartile 4 vs. Quartile 1: RR (95% CI) = 0.99 (0.73, 1.34) and 0.92 (0.49, 1.75) respectively). Similarly, no association was seen between CRP levels and riskof serrated polypsor proximal serrated polyps(Quartile 4 vs. Quartile 1: RR (95% CI) = 1.32 (0.85, 2.03) and 1.19 (0.54, 2.58) respectively. In conclusion, this large prospective colorectal adenoma chemoprevention study found no significant relationship between CRP levels and occurrence of adenomas, advanced neoplasms, or serrated polyps
