Hepatitis B virus infection and risk of colorectal cancer: a large, population-based cohort study from Israel.

Background: Recent population-based studies have suggested a possible link between hepatitis B (HBV) infection and extra-hepatic malignancies. We aimed to evaluate the association between HBV and colorectal cancer (CRC) using a large, population-based cohort study utilizing data from a large health maintenance organization (HMO).

Methods: The study included patients with non-cirrhotic HBV based on relevant ICD-9-CM codes and supportive serology identified from the HMO's database. Age-, sex-, ethnicity-, and BMI-matched non-HBV patients in a 1:10 ratio were included in the control group. We assessed the overall diagnosis rate of CRC and hepatocellular carcinoma (HCC) during the study period and calculated the diagnosis rate of CRC in each age category (≤50, 51-70, and ≥70) in both groups.

Results: A total of 3430 HBV patients and 34,300 controls were included in the study. The mean age, sex, BMI, and ethnic composition were similar, and the rates of family history of CRC did not differ between both groups. The overall follow-up period was 134±16 months. The diagnosis rate of HCC (1.6% vs. 0.1%; P<0.0001) was significantly higher in the HBV patients. However, the proportion of CRC was comparable for both groups (0.6% vs. 0.8%, P=0.404), which was evident in all age subgroups.

Conclusions: Our findings suggest that HBV infection is associated with an increased risk of HCC diagnosis but is not linked to an elevated risk of CRC. These findings may inform future clinical practice and research regarding the relationship between HBV and extrahepatic malignancies.