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Utilization Patterns and Survival in Older Men With Metastatic Prostate Cancer Treated with Radium-223 in the United States: A SEER-Medicare Study

Year: 2025

Type: article

Abstract: Structured Abstract Introduction Previous research on Radium-223 treatment patterns in metastatic prostate cancer has been limited to select sites, oncology practices, or claims databases. Limited data exists on the use and outcomes of Radium-223 in Medicare population the largest public insurance provider for people aged 65 years and older in the United States. Therefore, this study used a nationwide population database of cancer registries linked to Medicare claims to examine Ra-223 treatment patterns, factors associated with treatment completion, and their associations with survival outcomes. Patients and Methods A retrospective cohort analysis was conducted on 1,062 Medicare beneficiaries (≥66 years) with prostate cancer who initiated Ra-223 treatment between January 2016 and June 2020. Eligible men had 12 months of continuous Medicare Parts A/B/D enrollment prior to Ra-223 initiation and were followed for a minimum of 6 months. Primary outcomes included completion of ≥5 cycles of Ra-223 and overall survival. Factors influencing completion were analyzed with multivariate logistic regression, and survival was estimated using Kaplan-Meier and proportional hazards regressions. Results The cohort was 79.9% non-Hispanic White, 6.8% Hispanic, and 6.1% non-Hispanic Black, with a mean age of 75.6 years (SD=6.6). Overall, 59.4% completed ≥5 cycles. Men receiving Ra-223 as first-line (21.1%) or second-line metastatic castration-resistant prostate cancer(mCRPC) therapy (44.1%) were more likely to complete treatment than those receiving third-line or later (aOR=1.76,1.56, 95% CI=[1.22,2.54], [1.17,2.08]). Completing ≥5 cycles of Ra-223 was associated with longer survival (18.5 vs 11.1 months, p<0.001; aHR=0.51, 95%CI=[0.44, 0.59]), as was first- or second-line therapy use (18.4, 14.8 months vs 13.8 months, p<0.001; aHR=0.56, 0.82; 95%CI=[0.45, 0.68], [0.69,0.96]) compared to Ra-233 as third-line or later. Conclusion The majority of men received ≥5 cycles of Ra-223. Early initiation of Ra-223 was associated with higher completion rates and better survival outcomes, underscoring the importance of early Ra-223 use in managing mCRPC. Microabstract This study examined the real-world utilization and survival outcomes of Radium-223 (Ra-223) in 1,062 older men with metastatic castration-resistant prostate cancer (mCRPC) using SEER-Medicare data. A majority (59.4%) completed at least five cycles, and early initiation (first or second-line therapy) was associated with higher completion rates and improved survival. Findings underscore the importance of early Ra-223 use in mCRPC management.

Source: Clinical Genitourinary Cancer

DOI: 10.1016/j.clgc.2025.102372