Objectives: Inflammatory processes may influence the risk of epithelial ovarian cancer, but available epidemiological evidence is limited and indirect. Circulating C-reactive protein (CRP), a sensitive marker of inflammation, may serve as a direct biological marker of an underlying association.
Methods: The association between ovarian cancer risk and pre-diagnostic circulating CRP was tested in a case-control study nested within three prospective cohorts from Sweden, USA, and Italy. The study included 237 cases and 427 individually matched controls. CRP was measured in stored blood samples by high-sensitivity immunoturbidimetric assay. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by conditional logistic regression.
Results: Overall, CRP was not related to risk of ovarian cancer. However, a marked increase in risk was observed for CRP concentrations >10 mg/l: OR (95% CI) 4.4 (1.8-10.9), which remained significant after limiting analyses to cases diagnosed more than two or five years after blood donation (OR 3.0 (1.2-8.0) and 3.6 (1.0-13.2), respectively). Risk of mucinous tumors increased with high CRP, but the number of cases in this analysis was small.
Conclusion: Study results offer additional support to the concept that chronic inflammation plays a role in epithelial ovarian cancer.