HIV infection increases the risk for HPV-related cancers. This excess risk is due to a combination of increased sexual exposure to HPV infection and the influence of HIV-related immunodeficiency, as measured by CD4+ counts, on HPV natural history. Lower CD4+ counts have been shown to be associated with: 1) increased prevalence and persistence of cervical HPV infection, as well as the incidence of CIN2/3 and cervical cancer, 2) anal cancer incidence.
In order to estimate the burden of HPV-related cancer in persons infected with HIV (PHIV), we calculated incidence rates from record linkage between HIV/AIDS registries and cancer registries. Rates were applied to estimates of the population of PHIV in the United States in 2008 to obtain the total cancer burden. Site-specific attributable fractions and corresponding 95% confidence intervals (CIs) were estimated from infection prevalence among cancer cases derived from literature review of case series.
Of an estimated 6,200 incident cancer cases diagnosed among ~800,000 PHIV living in the USA in 2008, 632 cases (10% of all cancers) were attributed to HPV. A majority of these HPV-related cancers were anal cancers (n=425). Cervical, vulva, vagina, penis and oropharynx cancer accounted for 86, 39, 2, 9 and 70 cases respectively. Incidence rates of HPV-related cancer increased after age 30 in PHIV. MSM were the HIV transmission group with the highest HPV-related cancer burden, among whom anal incidence exceeds 100 per 100,000 person-years in the era of combined antiretroviral therapy (cART). In female PHIV living in less developed settings with no cervical screening, the burden of cervical cancer is much higher than that estimated for the USA PHIV population.
The burden of HPV-related cancer in the HIV-positive population is high but also amenable to prevention, namely via 1) early detection and treatment of HIV infection to avoid immunosuppression, 2) universal HPV vaccination, and 3) for cervical cancer in particular, detection and treatment of precancerous lesions.