Abstract 5729: PSA screening and the decreased risk of prostate cancer among men with AIDS
Authors: Shiels Meredith S. , Goedert James J. , Moore Richard D. , Platz Elizabeth A. , Engels Eric A. 
Published: February 2011

Background: Studies have reported lower prostate cancer rates among HIV+ men compared to the general population, consistent across recent calendar years. Because a large fraction of prostate cancers in the U.S. are detected by PSA screening, this deficit may be an artifact of a lower prevalence of screening among HIV+ men. We examined whether the risk of prostate cancer in strata defined by stage and demographic factors yielded results consistent with a screening bias. Additionally, we assessed the effect of stage at prostate cancer diagnosis on total mortality among men with AIDS.

Methods: We estimated the prevalence of PSA screening among HIV+ men in the Johns Hopkins HIV Clinical Cohort [JHHCC]. All other analyses used data from the HIV/AIDS Cancer Match [HACM] study, which links 15 U.S. HIV/AIDS and cancer registries. Standardized incidence ratios [SIRs] of prostate cancer were calculated for men with AIDS compared with the US population overall and within strata of age, race, CD4 cell count at AIDS, HIV transmission risk group, and cancer stage at diagnosis during the PSA era (1992-2003). We also calculated an SIR using rates from the pre-PSA era (1985-1987) to estimate the expected number of cases. We used Cox regression to evaluate the association between stage at prostate cancer diagnosis and death among men with AIDS.

Results: During 2000-2008, the mean prevalence of PSA screening was 1.2% per year among HIV+ men in the JHHCC. During the PSA era, 203 prostate cancers were detected in 321,360 men with AIDS in the HACM study. Prostate cancer incidence was significantly lower among men with AIDS compared to the general population overall (SIR=0.47; 95% CI 0.41, 0.54) and across age, race, CD4 cell count at AIDS, and HIV transmission risk groups. Risk of local (SIR=0.46; 95% CI 0.39, 0.54) and regional stage (SIR=0.12; 95% CI 0.05, 0.26) cancer was lower among men with AIDS, but there was no difference in risk of distant stage cancer (SIR=0.82; 95% CI 0.48, 1.32). Additionally, the deficit in prostate cancer risk among men with AIDS disappeared when compared to the general population in the pre-PSA era (SIR=1.07; 95% CI 0.93, 1.23). Among men with AIDS, local/regional stage cancer was not associated with death (hazard ratio [HR] =0.95; 95% CI 0.71, 1.29), but distant stage cancer was associated with elevated mortality (HR=4.67; 95% CI 2.91, 5.95).

Conclusion: The lower incidence of prostate cancer in HIV+ men compared to the U.S. general population plausibly reflects the low prevalence of PSA screening among HIV+ men. We also found that the effect of prostate cancer in increasing subsequent mortality among men with AIDS was similar to the effect for men in the general population (SEER standardized mortality ratio=0.86 for local/regional and 5.22 for distant stage prostate cancer). The lack of PSA screening among men with AIDS does not appear to have had an impact on the risk of aggressive cancer or subsequent cancer-related death.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 5729.