Different Metabolic Associations of Hepatitis C With Colon and Rectal Cancers: A 9-Year Nationwide Population-Based Cohort Study.

Background: Whether HCV infection is associated with colorectal cancer (CRC) development remains inconclusive.

Methods: A nationwide population-based cohort study of the Taiwan National Health Insurance Research Database was conducted.

Results: From 2003 to 2012, 1:2:2 propensity score-matched HCV-treated [interferon-based therapy ≥ 6 months, surveys for CRC (n = 9017), colon cancer (CC) (n = 9,022) and rectal cancer (RC) (n = 9,033), HCV-untreated and HCV-uninfected cohorts CRC (n = 18034), CC (n = 18,044) and RC (n = 18,066) were enrolled. The HCV-uninfected cohort had the lowest cumulative incidence of CRC (0.117%; 95% CI: 0.062%-0.207%), whereas the HCV-treated (0.966%; 0.375-2.122%) and HCV-untreated (0.807%; 0.485%-1.280%) cohorts had similar incidences (P = .0662); HCV infection [reference: HCV-untreated cohort, HCV-treated: hazard ratio (HR): 0.598; 95% CI HR: 0.337-1.059; HCV-uninfected: 0.250; 0.138-0.456] and age ≥ 49 years (3.128;1.751-5.59) were associated with CRC development. The HCV-untreated cohort had the highest cumulative incidence of CC (0.883%; 0.371-1.839%), while HCV-treated (0.478%; 0.110-1.518%) and HCV-uninfected cohorts (0.147%; 0.071-0.284%) had similar incidences (P = .4853); HCV infection (HCV-treated: 0.474; 0.232-0.971; HCV-uninfected: 0.338; 0.184-0.62), male sex (2.18; 1.301-3.654), age≥ 49 years (4.818; 2.123-10.936) and diabetes (1.983; 1.205-3.262) were associated with CC development. A higher RC cumulative incidence was noted in the HCV-untreated cohort (0.332%; 0.151-0.664%) than in the HCV-uninfected cohort (0.116%; 0.054-0.232%) (P = .0352); HCV infection (HCV-treated: 0.691; 0.295-1.617; HCV-uninfected: 0.424; 0.207-0.867), age ≥ 49 years (3.745, 1.576-8.898) and stroke (3.162; 1.366-7.322) were associated with RC development.

Conclusions: The baseline associations were HCV infection and age ≥ 49 years with CRC; male sex and diabetes with CC; and stroke with RC. Anti-HCV therapy might reverse the risk of HCV-related CC but not RC.