Trends of risk classification and primary therapy for Japanese patients with prostate cancer in Nara Uro-Oncological Research Group (NUORG)-a comparison between 2004-2006 and 2007-2009

Background: To assess the trends of risk classification and primary therapy in Japanese patients who were diagnosed with prostate cancer between 2004-2006 and 2007-2009. Methods: A total of 4752 patients who were newly diagnosed with prostate cancer at Nara Medical University and its 23 affiliated hospitals between 2004 and 2009 were enrolled. The differences in risk classification and primary therapy were compared in patients who were newly diagnosed between 2004-2006 (prior period) and 2007-2009 (latter period). Results: The proportion of patients with a high or greater risk significantly decreased in the latter period compared to the prior period (p < 0.001). The proportion of primary androgen deprivation therapy (PADT) was 50% in the prior period, and 40% in the latter period. On the other hand, the proportion of radiation therapy was 14% in the prior period, but 24% in the latter period. The proportion of radical prostatectomy was the same in the two periods (30%). The primary therapy was significantly different between the two periods (p < 0.001). Conclusions: Higher risk patients significantly decreased in the latter period compared to the prior period. The use of PADT also significantly decreased in the latter period. However, there were still higher risk patients in Japan, and the use of PADT was still common in patients with localized prostate cancer or locally advanced prostate cancer in Japan.