33. Gradually decreasing anal cancer incidence in the HIV+ population in the Netherlands after a decade of cART

Abstract

Background: Anal cancer incidence has been increasing in the combined antiretroviral therapy (cART) era in HIV+ patients. In this study we surveyed trends in anal cancer incidence between 1995 and 2012, and analysed a range of potential risk factors. Methods: We retrieved data for all patients diagnosed with anal cancer from the Dutch HIV observational cohort (ATHENA) database. Incidence rates were calculated per 100 000 person-years of follow-up (FU), for the whole period of 18 years, and per 2-year blocks. Potential risk factors were analysed in a uni- and multivariable Cox proportional hazard model. Results: For all HIV+ patients, men who have sex with men (MSM), and heterosexual men and women, respectively, the incidence of anal cancer was 83 (95% CI 70–99), 116 (95% CI 95–140), 44 (95% CI 21–83) and 12 (95% 3–30) per 100 000 person-years of FU. In 2005–2006, a peak in incidence rates was observed of 114 (95% CI 74–169) in the total HIV population and 168 (95% CI 103–259) among HIV+ MSM, followed by a decrease to 72 (95% CI 42–113) and 100 (95% CI 56–164), respectively, in 2011–2012. Low nadir CD4 (<110), alcohol abuse and smoking were significantly associated with anal cancer in MSM, with hazard ratios (HR) of 2.41 (95%CI 1.5–3.89), 2.23 (95% CI 1.28–3.89) and 1.60 (95% CI 1.07–2.41), respectively. Conclusions: Anal cancer remains a serious problem in predominantly HIV+ MSM; however, it seems that incidence rates are levelling off. A low nadir CD4 count, alcohol abuse and smoking are risk factors for the development of anal cancer.