Reduced risk of prostate cancer in U.S. Men with AIDS

Abstract

Background: Previous studies describe decreased prostate cancer risk in HIV-infected men. In the United States, prostate-specific antigen (PSA) screening is common and increases the detection of prostate cancer. We evaluated whether the prostate cancer deficit among men with AIDS reflects differential PSA screening.

Methods: Data from the U.S. HIV/AIDS Cancer Match Study were used to calculate standardized incidence ratios (SIR) for prostate cancer, comparing men with AIDS (N = 287,247) to the general population. Furthermore, we estimated PSA testing rates in the Johns Hopkins HIV Clinical Cohort.

Results: Prostate cancer rates increased over time in the general population and, beginning in the 1990s, were consistently higher than among men with AIDS. Men with AIDS had the same prostate cancer risk as the general population in the pre-PSA era (<1992, SIR = 1.00), but significantly reduced risk during the PSA era overall (1992-2007, SIR = 0.50) and across age, race, HIV risk group, antiretroviral therapy era, and CD4 counts. Local and regional stage prostate cancer risk was lower among men with AIDS (SIRs, 0.49 and 0.14, respectively), but distant stage cancer risk did not differ (SIR = 0.85). Among HIV-infected men ≥40 years old, PSA testing was uncommon (18.7% per year), but increased 2.4-fold from 2000 to 2008, after age adjustment.

Conclusion: Prostate cancer risk was decreased by 50% among men with AIDS compared with the general population. This deficit was limited to the PSA era and early stage cancers.

Impact: Our findings suggest that the prostate cancer deficit in HIV-infected men is largely due to differential PSA screening.

Figure 1. Prostate cancer incidence among men in the U.S. AIDS and general populations

Incidence rates in men with AIDS (points), smoothed incidence rates in men with AIDS (solid line), and smoothed incidence rates in men in the general population (dashed line) by calendar year. Incidence rates among men with AIDS and in the general population are age- and race-standardized to the 2000 U.S. population. Data are not presented prior to 1988, because only 3 prostate cancer cases occurred among men with AIDS during 1980–1987.