Primary Androgen-Depletion Therapy Prevails Not Only for Metastatic but Also for Nonmetastatic Hormone-Naïve Prostate Cancer in Japan-Recent Trends and Efficacy.

OBJECTIVE

To investigate the real-world use of primary androgen-deprivation therapy(PADT; gonadotropin-releasing hormone agonists[leuprorelin/goserelin]and antagonists[degarelix]/surgical castration), its clinical effectiveness, and the characteristics of Japanese patients with hormone-sensitive prostate cancer treated with PADT.

METHODS

In this retrospective, observational study, patients using PADT(≥1 record)in the 2016-2018 Japan Study Group of Prostate Cancer registry were followed up from their initial date of PADT until October 2018. The primary endpoints included prostate-specific antigen( PSA)response rate(PSA<4 ng/mL)and duration of initial treatment.

RESULTS

Of 1,895 patients, 47.7%, 24.4%, and 22.0% received leuprorelin, goserelin, and degarelix, respectively; 5.9% underwent surgical castration. The degarelix group had the highest median PSA at diagnosis(116.7 ng/mL)and proportion of patients with clinical Stage Ⅳ prostate cancer (72.9%)and Gleason score 9-10(59.7%). A concomitant antiandrogen was used in >80% and 70% of patients in the leuprorelin/goserelin and degarelix groups, respectively; bicalutamide was used most commonly(99.0%). Median duration of initial treatment was 20.8 months in the degarelix group and not yet reached in the leuprorelin/goserelin groups; continuation rates at 24 months were 44.6% and 81.6%/87.3%, respectively. The PSA response rate was the highest in the leuprorelin group(93.7%); median percentage change in PSA was comparable across all treatment groups(-99.1% to -99.8%).

CONCLUSIONS

Real-world use of PADT in patients with hormone-sensitive prostate cancer is likely based on its specific therapeutic attributes and patient characteristics.