Efficacy and Safety of Radium-223 for Castration-resistant Prostate Cancer With Bone Metastasis Before and After Docetaxel.

Background/aim: Radium-223 (Ra-223) therapy provides a survival benefit for castration-resistant prostate cancer (CRPC) patients with bone metastasis. The optimal timing of using Ra-223 has not been determined. We evaluated the efficacy and safety of Ra-223 before and after docetaxel (DOC) therapy.

Patients And Methods: We retrospectively reviewed 36 CRPC patients with bone metastasis who were treated with Ra-223 in our institution and satellite hospitals. Ra-223 was used before DOC (pre-DOC group) in 17 patients (47%) and after DOC (post-DOC group) in 19 patients (53%). The treatment completion rate of 6 cycles, progression-free survival (PFS), cause-specific survival (CSS) and occurrence rate of adverse events were compared between the groups.

Results: The median follow-up duration was 45 months. In the pre-DOC compared with the post-DOC group, treatment completion rate was significantly higher (94% vs. 52%, p<0.01), PFS was significantly longer (median: 8 vs. 5 months, p=0.024) and CSS was significantly longer (median: 32 vs. 15 months, p=0.028). The difference in CSS was significant in multivariate analysis. In the pre-DOC compared with the post-DOC group, the occurrence rate of grade ≥3 adverse events tended to be lower (6% vs. 36%, p=0.322), and the CSS tended to be longer (median: not reached vs. 45 months, p=0.208).

Conclusion: Ra-223 could be used more safely and more effectively for CRPC patients with bone metastasis before than after DOC therapy.