Improved prognosis of de novo metastatic prostate cancer after an introduction of life-prolonging agents for castration-resistant prostate cancer

Background: In Japan, since 2014, new treatments such as androgen receptor signaling inhibitors and cabazitaxel have become applicable for metastatic castration-resistant prostate cancer (mCRPC), leading to dramatic changes in treatment options. Objective: This study aims to evaluate the impact of recent advancements in treatment options on the overall survival (OS) of patients diagnosed with de novo metastatic castration-sensitive prostate cancer (mCSPC) in Japan. Methods: A retrospective analysis was conducted on 2450 Japanese men diagnosed with de novo mCSPC between 2008 and 2018. Patients were stratified into two groups based on the period of diagnosis: an earlier period (2008–2013) and a later period (2014–2018). OS was compared between earlier and later periods using Kaplan–Meier analysis in total and propensity score matched subpopulation as well as risk-stratified subgroups. Results: Patients diagnosed in the later period exhibited significantly improved OS compared to those diagnosed in the earlier period. The risk score, calculated based on ISUP grade group, LDH levels, and ALP levels, was a poor prognostic factor. In the later period, compared to the earlier period, there was no improvement in OS in the favorable-risk group, but a significant improvement was observed in the poor-risk group. Conclusion: It was suggested that the introduction of novel androgen receptor signaling inhibitors and chemotherapy treatment regimens since 2014 has led to improved survival outcomes for patients with de novo mCSPC, particularly those with poor-risk profiles. The findings highlight the impact of recent advancements in treatment on the prognosis of patients with metastatic prostate cancer in Japan.