Association between C-reactive protein and risk of cancer: a meta-analysis of prospective cohort studies

Associations between elevated C-reactive protein (CRP) and cancer risk have been reported for many years, but the results from prospective cohort studies remains controversial. A meta-analysis of prospective cohort studies was therefore conducted to address this issue.

Eligible studies were identified by searching the PubMed and EMBASE up to October 2012. Pooled hazard ratios (HR) was calculated by using random effects model.

Eleven prospective cohort studies involving a total of 194,796 participants and 11,459 cancer cases were included in this meta-analysis. The pooled HR per natural log unit change in CRP was 1.105 (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 a change of one natural log unit in CRP was 1.012 (95% CI: 1.006-1.018) for all-cancer. No evidence of publication bias was observed.

The results of this meta-analysis showed that the elevated levels of CRP are associated 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 performed to identify whether CRP, as a marker of inflammation, has a direct role in carcinogenesis.