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Anal cancers among HIV-infected persons: HAART is not slowing rising incidence
Presented by Nancy Crum-Cianflone (United States).
N. Crum-Cianflone1,2, K. Huppler Hullsiek2,3, A. Weintrob2, A. Ganesan2, V. Marconi2, R.V. Barthel2, S. Fraser2, B. Agan2, and the Infectious Disease Clinical Research Program
1Naval Medical Center San Diego, San Diego, United States, 2Infectious Disease Clinical Research Program, Bethesda, United States, 3University of Minnesota, Minneapolis, United States
Background: As HIV-infected persons are experiencing longer life expectancies, cancers are becoming important causes of morbidity. Anal cancer appears to occur at higher rates among HIV-infected persons compared to the general population's rate of 1.5 cases per 100,000 person-years (PYs), but little is known about rates over the epidemic and the impact of HAART.
Methods: We evaluated the incidence of, and the risk factors for, anal cancer (histopathologically confirmed squamous cell carcinomas) using longitudinal data from a prospective Natural History Study (1985-2008). Variables such as CD4 counts, HAART, AIDS events, and STIs utilized all available data between HIV diagnosis and the event/censoring time. Poisson regression and Cox proportional hazard models were utilized.
Results: Among 5,029 HIV-infected persons with 39,291 PYs of follow-up, anal cancer rates increased 5-fold from the pre-HAART (17 per 100,000 PYs) to HAART (91 per 100,000 PYs) era, p=0.007. Rates continued to increase, reaching 244 per 100,000 PYs in 2006-2008. At cancer diagnosis (N=20), the median age was 41 years, 95% were male, 55% white, 50% had a history of hepatitis B, 41% gonorrhea, and 10% syphilis. Cases had a median CD4 count of 375 cells/mm3, 41% had a VL< 400, 40% had a prior AIDS event, and 75% had received HAART. Those with anal cancer were more likely to have a prior AIDS event (HR 3.5, p=0.01); they also had lower CD4 counts (HR 0.9 per 50 cells, p=0.10) and more STIs (HR 1.9, p=0.21), but these were not significant. HAART was not protective (HR 2.8, p=0.19).
Conclusions: The rates of anal cancer have progressively increased over the HIV epidemic. As HIV patients are living longer, it may allow for sufficient time for anal cancer development, hence rates may continue to increase. HAART was not protective. Preventive strategies for anal cancer among HIV-infected persons are needed.
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