C‐reactive protein and colorectal cancer risk: A systematic review of prospective studies

Abstract

C-reactive protein is a sensitive but nonspecific systemic marker of inflammation. Several prospective studies have investigated the association of prediagnostic circulating C-reactive protein concentrations with the development of colorectal cancer, but the results have been inconsistent. We performed a systematic review of prospective studies of the association between prediagnostic measurements of circulating high-sensitivity C-reactive protein and development of invasive colorectal cancer. Authors of original studies were contacted to acquire uniform data. We combined relative risks (RR) for colorectal cancer associated with a one unit change in natural logarithm-transformed high-sensitivity C-reactive protein using inverse variance weighted random effects models. We identified eight eligible studies, which included 1,159 colorectal cancer cases and 37,986 controls. The summary RR per one unit change in natural log-transformed high-sensitivity C-reactive protein was 1.12 (95% confidence intervals [CI], 1.01-1.25) for colorectal cancer, 1.13 (95% CI, 1.00-1.27) for colon cancer, and 1.06 (95% CI, 0.86-1.30) for rectal cancer. The association was stronger in men (RR, 1.18; 95% CI, 1.04-1.34) compared to women (RR, 1.09; 95% CI, 0.93-1.27) but this difference was sensitive to the findings from a single study. Prediagnostic high-sensitivity Creactive protein concentrations were weakly associated with an increased risk for colorectal cancer. More work is needed to understand the extent to which circulating high-sensitivity C-reactive protein or other blood inflammatory markers are related to colonic inflammation. ' 2008 Wiley-Liss, Inc.Key words: meta-analysis; C-reactive protein; inflammation; colorectal neoplasms C-reactive protein (CRP) is a sensitive but nonspecific systemic marker of inflammation.1 CRP is produced mainly in the liver along with other acute-phase proteins in response to cytokines released by phagocytes during infection, trauma, surgery, burns, tissue infarction, advanced cancer and chronic inflammatory conditions.2-4 Several lines of evidence suggest that colorectal neoplasia may arise from colonic areas with chronic subclinical inflammation. 5 Investigators have hypothesized that CRP may act as a biomarker for chronic low-grade intestinal inflammation and the subsequent development of colorectal cancer.Several retrospective case-control studies have compared CRP concentrations between colorectal cancer patients and healthy controls, and have reported at least 10-fold higher concentrations in the cancer patients.6-9 These findings may be explained to some extent by reverse causality due to the host inflammatory response to existing advanced cancer among cases. Prospective studies, where CRP is measured long before cancer diagnosis in all participants, are thus required to answer whether CRP is associated with colorectal cancer incidence. Findings from such studies, however, have been inconsistent. The reasons underlying these heterogeneous findings need to be investigated, but no formal meta...

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

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Obesity Biomarkers, Metabolism and Risk of Cancer: An Epidemiological Perspective

“…A number of epidemiological studies investigated the association between biomarkers of chronic inflammation, particularly CRP and colorectal cancer risk. High blood concentrations of CRP have been associated with moderately higher CRC risk in several prospective studies [87][88][89] including in the EPIC study [90]. However, findings from observational studies relating circulating CRP to cancer risk may not necessarily reflect causal associations.…”

Prospective evaluation of C-reactive protein, smoking and lung cancer death in the Third National Health and Nutrition Examination Survey

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