Increased risk of anal squamous cell carcinoma in HIV-positive men with prior hepatitis B virus infection.

OBJECTIVE(S): HIV-positive individuals have elevated rates of anal squamous cell carcinoma (SCC), and sexually transmitted infections with its causative agent, high-risk human papillomavirus, and other oncoviruses including hepatitis B virus (HBV). HBV infection can cause liver cancer, and has been associated with increased risk of some extra-hepatic cancers including biliary tract cancer, pancreatic cancer, and non-Hodgkin lymphoma. Whether HBV is associated with anal SCC risk is unknown.

DESIGN

Prospective study of anal SCC risk in HIV-positive and HIV-negative MSM in the Multicenter AIDS Cohort Study from 1984 to 2014.

METHODS

Poisson regression models were used to examine the association between past or current HBV infection (positive tests for HBV core antibodies, surface antigen, and/or DNA) and anal SCC risk.

RESULTS

We observed 53 cases of anal SCC among 5298 participants with 79 334 person-years follow-up. Among HIV-positive men, past or current HBV infection was associated with anal SCC risk in models adjusted for age, CD4+ cell counts, HAART use, and other risk factors [incidence rate ratio (IRR), 95% confidence interval 3.15, 1.27-7.82]. Additional risk factors included immunological parameters 1 and 6 years prior to diagnosis (IRR, 95% confidence interval 2.45, 1.31-4.58 and 2.44, 1.3-4.59 for CD4+ cell counts <500 cells/μl; 2.43, 1.34-4.42 and 2.77, 1.5-5.11 for CD4+ : CD8+ ratios <0.5, respectively). Among HIV-negative men, IRR for prior HBV and anal SCC risk was similar, but NS due to small number of cases.

CONCLUSION

HIV-positive MSM with prior HBV infection have increased anal SCC risk. This population may benefit from screening.