The present study aimed to evaluate the optimal timing of radium-223 chloride (Ra-223) administration among patients with bone metastasis from castration-resistant prostate cancer (BmCRPC). Patients, who were diagnosed with BmCRPC and treated with Ra-223 therapy between October, 2016 and January, 2022, were reviewed. The survival time was calculated from the initiation of Ra-223 administration. The time from the diagnosis of BmCRPC to the initiation of Ra-223 administration was identified as a potential prognostic factor. A total of 51 patients were examined in the present study. Ra-223 was administered as the first- and second-line therapy (earlier Ra-223 administration) in 32 patients and as the third- to fifth-line therapy (later Ra-223 administration) in 19 patients. In the multivariate analysis, which considered the potential prognosis, the difference in survival times between patients who received early and late Ra-223 administration was not significant [hazard ratio (HR), 2.67; 95% confidence interval (CI), 0.79-9.07; P=0.11]. By contrast, an incomplete Ra-223 administration (HR, 128.03; 95% CI, 10.59-1548.42; P<0.01) and higher levels of prostate-specific antigen prior to Ra-223 administration (HR, 7.86; 95% CI, 2.7-27.24; P<0.01) were independent factors, significantly associated with a poorer prognosis. The timing of Ra-223 administration did not significantly affect the survival of patients from the initiation of treatment. Further studies are thus required to determine the optimal timing for Ra-223 administration.
Medicine international. 2023 Jul 11*** epublish ***
Kenji Makita, Yasushi Hamamoto, Hiromitsu Kanzaki, Natsumi Yamashita, Kei Nagasaki, Teruhito Kido, Noriyoshi Miura, Takashi Saika, Katsuyoshi Hashine
Department of Radiation Oncology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791-0280, Japan., Division of Clinical Biostatistics, Section of Cancer Prevention and Epidemiology, Clinical Research Center, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791-0280, Japan., Department of Radiology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan., Department of Urology, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan., Department of Urology, National Hospital Organization Shikoku Cancer Center, Matsuyama, Ehime 791-0280, Japan.