OBJECTIVES: To compare directly survival outcomes of primary androgen deprivation therapy (PADT) in Japan, where this treatment is endorsed by guidelines, with outcomes in the U.S., where it is not.
PATIENTS AND METHODS: Data were compared between men receiving PADT in the US CaPSURE registry and the Japanese J-CaP database. Competing risks regression was used to assess prostate cancer-specific mortality (CSM), adjusting for age, Japan Cancer of the Prostate Risk Assessment (J-CAPRA) score, diagnosis year, and treatment type (combined androgen blockade [CAB] vs. castration monotherapy), comorbidity, and practice type.
RESULTS: Men on PADT in J-CaP (N=13,880) were older than those in CaPSURE (N=1633), and had higher-risk disease (mean J-CAPRA score 3.8 vs. 2.1, p< 0.001). They more often received CAB: 66.9% vs. 46.4% (p< 0.001). Despite different risk profiles between the cohorts, CSM was similar on univariate analysis (log-rank p=0.88). On multivariable regression, the subhazard ratio for CSM was 0.52 for J-CaP vs. CaPSURE (95% CI 0.40-0.68).
CONCLUSIONS: Men on PADT in Japan have less than half the adjusted CSM than those in the US. These findings support existing both guidelines endorsing PADT in Asia and discouraging its use in the West. Elucidating the reasons behind these substantial differences-likely include both genetic and dietary/environmental factors-may help explain the varying epidemiology of prostate cancer on both sides of the Pacific.
Cooperberg MR, Hinotsu S, Namiki M, Carroll PR, Akaza H. Are you the author?
Department of Urology, UCSF Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, CA; Department of Epidemiology & Biostatistics, University of California, San Francisco, CA.
Reference: BJU Int. 2014 Sep 19. Epub ahead of print.