Circulating inflammation markers and colorectal adenoma risk.

Inflammation is a driver of colorectal neoplasia; however, what particular inflammatory processes play a role in early carcinogenesis are unclear. We compared serum levels of 78 inflammation markers between 171 pathologically confirmed colorectal adenoma cases (including 48 incident cases) and 344 controls within the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. We used weighted multivariable logistic regression to compute odds ratio (OR) and 95% confidence interval (CI). We found 14 markers associated with risk of adenoma overall; three of these were also associated with incident adenoma: CCL20 [overall adenoma 4th vs. 1st quartile: OR 4.8, 95% CI 2.0 to 12, Ptrend 0.0007; incident adenoma 3rd vs. 1st tertile OR 4.6, 95% CI 1.0 to 22, Ptrend 0.03], GRO [OR 3.8, 95% CI 1.6 to 9.3, Ptrend 0.006 and OR 3.6, 95% CI 1.1 to 12, Ptrend 0.04, respectively] and insulin [OR 2.9, 95% CI 0.8 to 10, Ptrend 0.05 and OR 7.8, 95% CI 1.3 to 46, Ptrend 0.03, respectively]. All statistical tests were two-sided. These results provide important new evidence implicating CCL20- and GRO-related pathways in early colorectal carcinogenesis, and further support a role for insulin.