Efficacy Of Sequential Therapy Comprising Of Docetaxel, Abiraterone, Enzalutamide, And Cabazitaxel In Patients With Castration-Resistant Prostate Cancer

239 Background: The sequence of use of life-prolonging therapy (docetaxel, abiraterone, enzalutamide, and cabazitaxel) is unclear in patients with castration-resistant prostate cancer (CRPC). Methods: We retrospectively identified a total of 316 patients diagnosed with CRPC from September 2003 to April 2019 at Nagoya University and its affiliated hospitals. All patients were treated with >2 life-prolonging therapies. We divided these patients into four groups based on the sequence of drug administration. The group of patients who were treated using the sequence of abiraterone to enzalutamide or enzalutamide to abiraterone was termed as AA. The group treated using the sequence of abiraterone or enzalutamide to docetaxel was termed as AD. The group treated using the sequence of docetaxel to abiraterone or enzalutamide was termed as DA. Lastly, the group treated using the sequence of docetaxel to cabazitaxel was termed as DC. We investigated the overall survival (OS) from the time of diagnosis of CRPC. In addition, we estimated combined progression-free survival (combined PFS) defined as the sum of the PFS of each agent. Results: The number of patients in AA, AD, DA, and DC was 106, 69, 130, and 11, respectively. Regarding AA, AD, DA, and DC, the median ages were 72, 70, 68, and 64 years, respectively. The proportion of patients who had de novo distant metastasis was 66%, 65%, 58%, and 73% in AA, AD, DA, and DC, respectively. Further, the median OS was 68.7, 54.5, 68.6, and 22.0 months for AA, AD, DA, and DC, respectively. Notably, no significant differences related to OS were observed between AA and AD ( p = 0.06), AA and DA ( p = 0.24), as well as AD and DA ( p = 0.46). The median combined PFS was 8.6, 10.1, 13.9, and 5.6 months for AA, AD, DA, and DC, respectively. In terms of combined PFS, a significant difference was observed between AA and DA ( p < 0.001) as well as AD and DA ( p = 0.003). OS and combined PFS were significantly poor in DC compared with those in the other groups. Conclusions: No significant differences related to OS were observed regarding the sequence of use of docetaxel, abiraterone, and enzalutamide. Notably, combined PFS was comparatively better in DA than in any other group.