Prostate cancer news reports: Friday, May 8, 2009

In today’s news reports we address such issues as:

  • The possibility that type of initial treatment and comorbidities explain at least some racial disparities in prostate cancer survival
  • Failure of time to surgery to explain racial disparities in post-treatment outcome
  • Once-weekly bicalutamide as a regimen to prevent prostate cancer

Holmes et al. have analyzed the impact of disparities  in use of androgen deprivation therapy (ADT) and the degree to which it affects racial differences in survival. They used Surveillance, Epidemiology and End Results (SEER) Medicare- linked data to define a large cohort of men (N = 64,475) diagnosed with locoregional prostate cancer between 1992 and 1999 and followed through 2003. The receipt of ADT was lower in African Americans (24 percent) than in Caucasians (27 percent), Asians (34 percent), and Hispanics (28.7 percent). African American race was also associated with increased mortality (HR = 1.26, 95% CI = 1.21-1.32) compared to Caucasian ethnicity. This difference was still significant after adjusting for ADT but was decreased after controlling for primary therapies such as radical prostatectomy, radiation, and watchful waiting and was no longer statistically significant after controlling for comorbidities. The authors conclude that, “racial disparities in survival were not affected by racial variations in ADT but were explained by racial variations in primary therapies and by racial differences in comorbidities.”

In a separate study, Bañez et al. identified 1,532 African American and Caucasian men who underwent radical prostatectomy (RP) between 1988 and 2007 at one of four Veterans Affairs Medical Centers that comprise the Shared Equal-Access Regional Cancer Hospital (SEARCH) database and whose biopsy date was known. Median time interval from diagnosis to RP was 76 and 68 days for African Americans and Caucasian men, respectively. However, after controlling for demographic and clinical variables, race was not associated with the time interval between diagnosis and RP. Therefore treatment delays do not explain prior findings of poorer outcomes among African Americans compared to Caucasians in an equal access medical system.

Zanardi et al. have conducted a phase I-II trial of bicalutamide once weekly in 80 men with a PSA > 4 ng/ml and negative biopsies as a method to prevent prostate cancer. The men were each assigned to one arm of a three-arm trial of bicalutamide 50 mg/wk (n = 26), bicalutamide 100 mg/wk (n = 28), or no treatment (n = 26) for 6 months. Blood samples were obtained at 0, 3, and 6 months, and prostate biopsies were repeated after 6 months. The results indicated that bicalutamide once weekly had some limited preventive impact because it reduced the prevalence of high-grade prostatic intraepithelial neoplasia; however, asymptomatic breast swelling was noted in 40 percent of the treated cases. The authors suggest that these data are good enough to support further studies of weekly bicalutamide as a preventive agent. The “New” Prostate Cancer InfoLink is significantly less confident that this is a wise idea.

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