Skeletal-related events (SREs) and survival among elderly patients with stage IV prostate cancer (PCa) in SEER Medicare data.

Abstract

249 Background: Skeletal-related events occurring among PCa patients with bone metastasis include radiation to the bone (RttB), pathological fracture, spinal cord compression (SCC), and bone surgery (BS). There is no validated algorithm for identifying RttB using claims data. We investigated the prevalence and mortality impact of SREs across alternative claims-based algorithms for identifying RttB. Methods: We analyzed data for stage IV PCa cases identified between 2005 and 2009 in the Surveillance, Epidemiology, and End Results registry linked with Medicare claims. Fracture, SCC, and BS were identified from claims. Focusing on external beam radiation therapy, radiopharmaceutical therapy, intensity modulated radiotherapy and stereotactic radiosurgery, three approaches were created based on data visualization software: 1) radiation claim occurred after a claim with a bone metastasis (BM) code; 2) BM code directly coincided with the period of the radiation treatment episode; 3) either #2 or the duration of the radiation episode was less than or equal to 4 weeks. Regression models for all-cause mortality used these measures. Results: The study sample included 5,380 men with stage IV PCa. The median age of the sample was 77 years. All-cause mortality was 54% during median (mean) follow-up of 579 (656) days. The proportion who had any fracture, SCC, and BS was 23.2%, 6.3%, and 5.8%. Without taking BM code or duration of radiation into consideration, the proportion who received radiation therapy was 35%. Using approaches 1, 2 and 3 we have the following four results: 1) the proportion who received RttB was 22%, 18%, and 24%; 2) the prevalence of any SRE was 39%, 37%, and 41%; 3) among those with an SRE, the proportion receiving RttB was 57%, 50%, and 58%; 4) the adjusted hazard ratio (95% CI) associated with any SRE was 1.22 (1.13–1.33), 1.22 (1.12–1.33), and 1.25 (1.15–1.36). Conclusions: Among older men diagnosed with stage IV prostate cancer, approximately one in five men received palliative radiation and the mortality impact of skeletal-related events was comparable across alternative approaches to identifying palliative radiation.