Thanks to improvements in HIV treatment and care the prognosis of many HIV-positive patients is now near normal. However, HIV-positive patients appear more likely to develop certain malignancies, including anal cancer, compared to their HIV-negative peers.
Understanding the incidence of anal cancer in the different populations affected by HIV can help develop strategies to prevent the cancer.
Therefore investigators from the North American AIDS Cohort Collaboration on Research and Design (NA-ACCORD) analysed findings from 13 US and Canadian studies. Their aims was to determine incidence of anal cancer in HIV-positive patients, who were divided into three categories – MSM, other men and women.
Rates of anal cancer in these HIV-positive patients were compared to those observed in HIV-negative men and women. Analyses were also conducted to see if there were temporal trends in anal cancer incidence, and if any specific risk factors for the malignancy in HIV-positive patients could be identified.
A total of 34,000 HIV-positive patients (55% MSM, 19% other men, 26% women) and 110,000 HIV-negative controls (90% men) were included in the study.
Data gathered between 1996 (the year effective HIV therapy first became available) and 2007 were examined by the investigators.
Incidence of anal cancer in MSM was 131 per 100,000 patient years. Among HIV-positive other men incidence of the malignancy was 46 per 100,000 years, and incidence in HIV-positive women was 30 per 100,000 person years. Incidence was therefore significantly higher in HIV-positive MSM compared to other men (p < 0.01). However, incidence rates for HIV-positive other men and women did not differ significantly.