Recent and projected incidence trends and risk of anal cancer among people with HIV in North America

Abstract

Background Anal cancer risk is elevated among people with HIV (PWH). Recent anal cancer incidence patterns among PWH in the United States (US) and Canada remain unclear. It is unknown how the incidence patterns may evolve in future years. Methods Using data from the North American AIDS Cohort Collaboration on Research and Design, we investigated absolute anal cancer incidence and incidence trends in the US, Canada, and different US regions. We further estimated relative risk compared with persons without HIV, relative risk among various subgroups, and projected future anal cancer burden among US PWH. Results During 2001-2016, in the US, age-standardized anal cancer incidence declined 2.2%/year (95%CI=-4.4% to -0.1%), particularly in the Western region (-3.8%/year [95%CI=-6.5% to -0.9%]. In Canada, incidence remained stable. Considerable geographic variation in risk was observed by US regions (eg, over four-fold risk in the Midwest and Southeast compared to the Northeast among men who have sex with men [MSM] with HIV). Anal cancer risk increased with a decrease in nadir CD4 count and was elevated among those with opportunistic illnesses. Anal cancer burden among US PWH is expected to decrease in future years (through 2035), but >70% of cases will continue to occur in MSM with HIV and people with AIDS. Conclusion Geographic variation in anal cancer risk and trends may reflect underlying differences in screening practices and HIV epidemic. MSM with HIV and PWH with AIDS will continue to bear most anal cancer burden, highlighting the importance of precision prevention.