Tanaka M, Kimura T, Iwamura Y, et al. - Researchers intended to re-investigate the rationale for the clinical guidelines regarding cycles of docetaxel (DOC) in castration-resistant prostate cancer (CRPC). A total of 122 CRPC individuals received at least five cycles of DOC at Jikei University and its affiliated hospitals. The ex- and short-DOC groups involved 80 and 42 patients, respectively. Among groups, most baseline demographics did not vary. Nevertheless, in the short-DOC group, more patients had received abiraterone acetate and/or enzalutamide prior to chemotherapy, age at DOC induction was younger, and lactate dehydrogenase at DOC induction was greater. In the ex-DOC group vs the short-DOC group, overall survival was significantly prolonged. A subgroup of 22 patients in the adverse events (AE) group was contrasted to recompense for potential bias. Among the AE group and ex-DOC groups, overall survival from the induction of DOC was relative. Univariate and multivariate analyses did not reveal any benefit of the extensive use of DOC on individual survival. Therefore, in the era of innovative drugs such as abiraterone acetate, enzalutamide, and cabazitaxel, the results of this study failed to demonstrate the survival advantage of extensive use of DOC over 10 cycles in CRPC individuals. Further prospective studies are needed to validate these findings.