余秉軒¹、林子平^1,2,3、魏子鈞^1,2,3、黃奕燊^1,2,3、林志杰^1,2,3、黃逸修^1,2,3、鍾孝仁^1,2,3、

盧星華^1,2,3、郭俊逸^1,2,3、張延驊^1,2,3、陳光國^1,2,3、黃志賢^1,2,3

¹臺北榮總泌尿部；²國立陽明大學醫學系泌尿學科；³書田泌尿科學研究中心  

Ping-Hsuan Yu¹, Tzu-Ping Lin ^1,2,3, Tzu-Chun Wei^1,2,3, I-shen Huang^1,2,3,

Chih-Chieh Lin^1,2,3, Eric Yi-Hsiu Huang^1,2,3, Hsiao-Jen Chung^1,2,3, Shing-Hwa Lu^1,2,3,

Junne-Yih Kuo^1,2,3, Yen-Hwa Chang^1,2,3, Kuang-Kuo Chen^1,2,3, William J.S. Huang^1,2,3

¹ Department of Urology, Taipei Veterans General Hospital;

² Department of Urology, School of Medicine, National Yang-Ming University;

³Shu-Tien Urological Science Research Center, Taipei, Taiwan

 

Purpose: According to COU-AA 302 trial, abiraterone is beneficial to chemo-naïve castration resistant prostate cancer (CRPC) patients in terms of radiographic progression-free survival and overall survival. Other studies evaluate the possible prognostic factors such as baseline PSA level or PSA decline percentage based on the dataset of COU-AA 302. Due to the possible different prostate cancer behavior related to different ethnicity, studies from non-Caucasian countries, such as Japan, deal with prognostic factors based on their cohort. For lack of Taiwanese data, here we would like to study possible prognostic factors based on a Taiwanese chemo-naïve cohort treated with abiraterone.

Materials and Methods: Clinical data of chemo-naïve CRPC patients treated with abiraterone in a single Taiwanese institute were reviewed from July 2017 to August 2019. Clinical parameters analyzed include Gleason grouping, baseline PSA level, PSA decline percentage, concurrent analgesic agents, PSA doubling time, and PSA velocity. Endpoints of interest include radiographic progression free survival (rPFS), overall survival (OS), and time to PSA progression (TTPP). Kaplan-Meier and Cox regression were used for statistical analysis.

Results: A total of 68 patients were included, with a mean age of 80.03±10.41 years old and average follow-up time 14.31±6.85 months. If biochemical response exists, the average time from the first dose of abiraterone to the PSA nadir is 5.55±4.25 months. Until Sep. 1^st 2019, there were still 30 patients taking abiraterone while the rest 38 patients stopped to use it.

Patients without analgesics usage has trends of longer rPFS and TTPP (rPFS: 14.70 vs 9.54 months, p=0.09; TTPP: 12.08 vs 7.16 months, p=0.078), and has significant longer overall survival (OS: 19.682 vs 13.464, p=0.007). Baseline PSA does not show impacts on rPFS, but on OS and TTPP although not statistically significant (OS: p=0.084; TTPP: p=0.167). The PSA decline percentage under abiraterone usage significantly influences all the three endpoints (rPFS: p=0.015; OS: p=0.03; TTPP: p<0.001). In patients with Gleason group 4 or less, there is a trend of longer overall survival compared to that of Gleason group 5 patients (OS: 19.583 vs 15.548, p=0.06). Those with PSA doubling time longer than four months have a significant longer overall survival (OS: 15.778 vs 20.411, p=0.016), and those with PSA velocity less than 10 ng/ml per month has a significant longer overall survival as well (OS: 20.073 vs 14.916, p=0.015). Patients taking companion dexamethasone seems to fare better comparing to those taking prednisolone numerically (rPFS: 9.799 vs 15.467, p=0.068; OS: 15.862 vs 18.52, p=0.314; TTPP 8.028 vs 11.945, p=0.184).

Conclusions: Among these potential prognostic factors in chemo-naïve abiraterone for the Taiwanese population, PSA decline percentage significantly relates to rPFS, OS, and TTPP. Patients with analgesics usage, PSA doubling time less than four months, and PSA velocity more than 10ng/ml per month have a significant shorter overall survival.