Time to progression to castration-resistant prostate cancer after commencing combined androgen blockade for advanced hormone-sensitive prostate cancer

// Satoshi Tamada 1 , Taro Iguchi 1 , Minoru Kato 1 , Jumpei Asakawa 1 , Kazuaki Kita 1 , Sayaka Yasuda 1 , Takeshi Yamasaki 1 , Yudai Matsuoka 2 , Kazuyuki Yamaguchi 2 , Kentaro Matsumura 2 , Ishun Go 2 , Tetsuji Ohmachi 2 and Tatsuya Nakatani 1 1 Department of Urology, Osaka City University Graduate School of Medicine, Abeno-ku, Osaka 545–8585, Japan 2 Department of Urology, Bell Land General Hospital, Naka-ku, Sakai City, Osaka 599–8247, Japan Correspondence to: Satoshi Tamada, email: s-tamada@med.osaka-cu.ac.jp Keywords: castration-resistant prostate cancer; combined androgen blockade; hormone-sensitive prostate cancer; progression; survival Received: September 19, 2018      Accepted: November 26, 2018      Published: December 11, 2018 ABSTRACT Purpose: The aim of our retrospective study was to determine the time to progression to castration-resistant prostate cancer (CRPC) in prostate cancer patients who undergo combined androgen blockade (CAB), as well as their prognoses. Materials and Methods: We examined the overall survival (OS) and disease-specific survival rates, as well as the time to CRPC development, in 387 patients who were treated with CAB for prostate cancer. The disease-specific survival rate and time to CRPC were stratified by prostate-specific antigen (PSA) levels, Gleason score (GS), and presence of metastasis at diagnosis. We designated high-risk patients as those satisfying at least two of the following three criteria: extent of disease of bone metastasis grade ≥2, presence of metastasis at diagnosis, and a GS ≥8. Results: The 10- and 15-year OS rates were 74.0% and 50.4%, respectively, while the corresponding disease-specific survival rates were both 86.8%. Metastasis at diagnosis was an independent prognostic factor for disease-specific survival. The median time to CRPC development was 140.7 months. A PSA level ≥20 ng/mL, a GS ≥8, and the presence of metastasis at diagnosis were independent predictors of a shorter time to CRPC development. The 10-year disease-specific survival rate in the high-risk group was significantly lower than that in the low-risk group (approximately 74% vs. 98%), and the time to CRPC development was significantly shorter (median: 20.5 months vs. not reached). Conclusions: The time to CRPC development was shorter in high-risk prostate cancer patients with metastases. Such patients require alternative novel treatment modalities.