Protease Inhibitors Linked to Higher Anal Cancer Rate in US Group
Longer treatment with protease inhibitors (PIs) independently raised the anal cancer rate in a study of men and women in California’s Kaiser Permanente healthcare system. Longer antiretroviral use lowered rates of AIDS-defining cancers.
To learn more about changing AIDS and non-AIDS cancer rates in the current antiretroviral era, Kaiser Permanente researchers identified cancers from Surveillance, Epidemiology, and End Results (SEER)-based cancer registries and divided them into AIDS cancers, infection-related non-AIDS cancers, and noninfection-related non-AIDS cancers. The Kaiser team figured the impact of antiretroviral therapy (ART), duration of any ART, and duration of PI or nonnucleoside ART on cancer rates.
The analysis covered 32,368 person-years of ART, 21,249 person-years of PI use, and 15,643 person-years of nonnucleoside use. Follow-up duration averaged 4.5 years.
Every year of ART cut the AIDS cancer rate almost 40% (rate ratio [RR] per year 0.61, 95% confidence interval [CI] 0.56 to 0.66). Considered separately, duration of PI use and duration of nonnucleoside use had a similar impact on the AIDS cancer rate.
Duration of ART, duration of PI use, and duration of nonnucleoside use did not affect rates of infection-related non-AIDS cancers or noninfection-related non-AIDS cancers, with one exception: Each year of PI use raised the anal cancer rate 16% (RR per year 1.16, 95% CI 1.02 to 1.31). Anal cancer may be caused by infection with human papillomavirus, a sexually transmitted infection.
The researchers proposed that “long-term use of protease inhibitor[s] . . . might be associated with increased anal cancer risk.”
Source: Chun Chao, Wendy A. Leyden, Lanfang Xu, Michael A. Horberg, Daniel Klein, William J. Towner, Charles P. Quesenberry, Jr, Donald I. Abrams, Michael J. Silverberg. Exposure to antiretroviral therapy and risk of cancer in HIV-infected persons. AIDS. 2012; 26: 2223-2231.
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Written by Mark Mascolini on behalf of the International AIDS Society