去勢敏感性前列腺癌病人於雄激素剝奪治療期間的睪丸激素突破率

張乃文¹、陳文榮^1,2,3

¹中山醫學大學附設醫院 泌尿科， ²醫學院， ³醫學研究所

Testosterone Breakthrough Rates during Androgen Deprivation Therapy for Castration Sensitive Prostate Cancer

Nai-Wen Chang¹, Wen-Jung Chen^1,2,3

Department of Urology¹, School of Medicine² and Institute of Medicine³, Chung Shan Medical University Hospital, Taichung, Taiwan

Purpose: We compare the breakthrough rate of two castration threshold (20 and 50 ng/dl) and time to progression to castrate-resistant prostate cancer (CRPC) of the subgroup(<20, 20-50 and >50 ng/dl). We wonder whether the lower castration threshold group has significant higher breakthrough rate and testosterone levels below the lower castration threshold (20 ng/dl) have a significant increased time to progression to CRPC.

Materials and Methods: We retrospectively included patients undergoing androgen deprivation therapy (ADT) with luteinizing hormone- releasing hormone agonist or antagonist at CSMUH from 2017 to 2020. ADT was administrated at least six months. Serum testosterone level was assessed every 6~12 months and PSA was assessed every 3 months. End points was time to progression (TTP) including PSA biochemical failure and/or ≥ sites of osseus or soft tissue metastasis. Patients were distributed into groups with cutoff testosterone levels 20 and 50 ng/dl. Time to progression to CRPC was assessed with the Kaplan-Meier method and compared with the log-rank test.

Results: A total of 50 patients were included in this study. Mean patient follow-up was 39 months. Testosterone breakthrough between 20 and 50 ng/dl was observed in 24 patients (48%) and greater than 50 ng/dl was observed in the 10 (20%). Significantly higher breakthrough rates were seen for the 20 ng/dl threshold compared to 50 ng/dl (p = 0.01). However, a significant association between breakthrough rates and worse clinical outcomes overall was not found no matter what threshold used. A testosterone breakthrough threshold of 20 ng/ dL or 50 ng/dL did not significantly predict with time to progression to CRPC (p = 0.393 and 0.827, respectively). Mean survival free of progression in patients with testosterone greater than 50 ng/dl was 34.6 months (95% CI 21.5–47.6), 34.6 months (95% CI 26.8-42.5) in testosterone 20-50 ng/dl, while it was 44.8 months (95% CI 30.5-59.1) in testosterone lower than 20 ng/dl.

Conclusion: Although the testosterone breakthrough rate was significantly higher in 20 ng/dl threshold, there was no difference in time to progression to CRPC between 20 or 50 ng/dl threshold. Testosterone breakthroughs was likely to result in worse clinical outcomes and should be avoided.