Naoki Fujita1, Shingo Hatakeyama2, Masaki Momota1, Yuki Tobisawa1, Tohru Yoneyama3, Hayato Yamamoto1, Atsushi Imai1, Hiroyuki Ito4, Takahiro Yoneyama3, Yasuhiro Hashimoto1, Kazuaki Yoshikawa5, Yasushi Mariya6, Chikara Ohyama7. 1. Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. 2. Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. Electronic address: shingoh@hirosaki-u.ac.jp. 3. Department of Advanced Transplant and Regenerative Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan. 4. Department of Urology, Aomori Rosai Hospital, Hachinohe, Japan. 5. Department of Urology, Mutsu General Hospital, Mutsu, Japan. 6. Department of Radiology, Mutsu General Hospital, Mutsu, Japan. 7. Department of Urology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan; Department of Advanced Transplant and Regenerative Medicine, Hirosaki University Graduate School of Medicine, Hirosaki, Japan.
Abstract
INTRODUCTION: The objective of this study was to evaluate the safety and feasibility of radiation therapy (RT) to the primary tumor in patients with metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: This retrospective study included 105 patients with mCRPC who were treated between April 2004 and May 2019. We divided the patients into 2 groups: patients treated with RT to the primary tumor after they developed CRPC (RT group) and without (non-RT group). The primary purpose was safety assessed using the Common Terminology Criteria for Adverse Events. The secondary purpose included prostate-specific antigen (PSA) response, cancer-specific survival (CSS), and overall survival (OS). Background-adjusted multivariate analyses, with the inverse probability of treatment weighting (IPTW) method, were performed to evaluate impact of RT on CSS and OS. RESULTS: The median age at CRPC diagnosis was 75 years, and the median follow-up period after CRPC diagnosis was 21 months. The adverse events rates related to RT in any grade and grade ≥ 3 were 55% and 23%, respectively. Nine (29%) patients achieved ≥ 30% PSA decline with RT. In multivariate analyses with the IPTW method, the CSS and OS in the RT group were significantly longer than those in the non-RT group. In subgroup analyses with the IPTW method, RT was significantly associated with improved OS in patients aged ≥ 75 years and patients with initial PSA ≥ 500 ng/mL, cT4, Gleason score ≥ 8, and high-volume metastatic burden. CONCLUSIONS: RT to the primary tumor is safe and feasible, and it has potential benefits on oncologic outcomes in patients with mCRPC.
INTRODUCTION: The objective of this study was to evaluate the safety and feasibility of radiation therapy (RT) to the primary tumor in patients with metastatic castration-resistant prostate cancer (mCRPC). PATIENTS AND METHODS: This retrospective study included 105 patients with mCRPC who were treated between April 2004 and May 2019. We divided the patients into 2 groups: patients treated with RT to the primary tumor after they developed CRPC (RT group) and without (non-RT group). The primary purpose was safety assessed using the Common Terminology Criteria for Adverse Events. The secondary purpose included prostate-specific antigen (PSA) response, cancer-specific survival (CSS), and overall survival (OS). Background-adjusted multivariate analyses, with the inverse probability of treatment weighting (IPTW) method, were performed to evaluate impact of RT on CSS and OS. RESULTS: The median age at CRPC diagnosis was 75 years, and the median follow-up period after CRPC diagnosis was 21 months. The adverse events rates related to RT in any grade and grade ≥ 3 were 55% and 23%, respectively. Nine (29%) patients achieved ≥ 30% PSA decline with RT. In multivariate analyses with the IPTW method, the CSS and OS in the RT group were significantly longer than those in the non-RT group. In subgroup analyses with the IPTW method, RT was significantly associated with improved OS in patients aged ≥ 75 years and patients with initial PSA ≥ 500 ng/mL, cT4, Gleason score ≥ 8, and high-volume metastatic burden. CONCLUSIONS: RT to the primary tumor is safe and feasible, and it has potential benefits on oncologic outcomes in patients with mCRPC.