Association Between C-reactive Protein and Risk of Cancer: A Meta-analysis of Prospective Cohort Studies

Background: Associations between elevated C-reactive protein (CRP) and cancer risk have been reported formany years, but the results from prospective cohort studies remains controversial. A meta-analysis of prospectivecohort studies was therefore conducted to address this issue.
Methods: Eligible studies were identified bysearching the PubMed and EMBASE up to October 2012. Pooled hazard ratios (HR) was calculated by usingrandom effects model.
Results: Eleven prospective cohort studies involving a total of 194,796 participants and11,459 cancer cases were included in this meta-analysis. The pooled HR per natural log unit change in CRP was1.105 (95% confidence interval (CI): 1.033-1.178) for all-cancer, 1.308 (95% CI: 1.097-1.519) for lung cancer,1.040 (95% CI: 0.910-1.170) for breast cancer, 1.063 (95% CI: 0.965-1.161) for prostate cancer, and 1.055 (95%CI: 0.925-1.184) for colorectal cancer. Dose-response analysis showed that the exponentiated linear trend for achange of one natural log unit in CRP was 1.012 (95% CI: 1.006-1.018) for all-cancer. No evidence of publicationbias was observed.
Conclusions: The results of this meta-analysis showed that the elevated levels of CRP areassociated with an increased risk of all-cancer, lung cancer, and possibly breast, prostate and colorectal cancer.The result supports a role of chronic inflammation in carcinogenesis. Further research effort should be performedto identify whether CRP, as a marker of inflammation, has a direct role in carcinogenesis.