Chronic hepatitis C as a risk factor for colorectal adenoma

Over the last decade, epidemiologic studies have determined a relationship between chronic hepatitis C (CHC) and malignancies other than hepatocellular carcinoma (HCC), particularly in gastrointestinal malignancies. This study aims to evaluate the incidence of colorectal adenomas and advanced neoplasia in CHC patients compared to the general population and to evaluate whether CHC infection is an independent risk factor for colorectal adenomas and advanced neoplasia.

This is a retrospective, case-control study. CHC patients who underwent screening colonoscopy between September 2006 and September 2010 were compared to randomly selected non-hepatitis C controls undergoing screening colonoscopy during the same period. Multivariate analysis was performed taking into account the known risk factors for colorectal adenoma.

Two hundred thirty-three CHC patients and 466 controls that underwent screening colonoscopy were included in the study. CHC patients were younger and more likely to be male, smoker and have HIV infection compared to the control group (p < 0.05). CHC group had a significantly higher number of patients with adenomas (adenoma detection rate of 37.8 vs. 30.3 %; p = 0.04) and hyperplastic polyps (p = 0.01) detected on screening colonoscopy. The total number of adenomas detected was also higher in the CHC group; however, this was not statistically significant (0.69 vs. 0.58 per patient; p > 0.05). CHC patients were twice more likely to have advanced neoplasia detected compared to non-hepatitis C patients (odds ratio 2.04, 95 % confidence interval = 1.20-3.49; p = 0.03). CHC group was also more likely to have adenomas of ≥6 mm (p = 0.005) and macroadenomas of ≥1 cm (p = 0.02).

Limitations include the single-center, retrospective design of the study.

Our study is the first to demonstrate a significantly higher rate of adenomas, advanced neoplasia, and hyperplastic polyps in CHC patients compared to the general population. On multivariate analysis, CHC infection was found to be an independent risk factor for colorectal adenoma, particularly advanced neoplasia. Larger prospective studies are needed to strengthen our findings which may have implications for colorectal cancer screening.