Skeletal-related events (SREs), baseline comorbidity, and survival among elderly patients (pts) with metastatic (M1) prostate cancer (PCa) in SEER-Medicare.

Abstract

e16027 Background: The prevalence of comorbidities increases with age in older men diagnosed with M1 PCa. However, the relationship between comorbidities, PCa, SREs, and mortality is not well understood. Methods: We analyzed pts aged 66+ diagnosed with M1 PCa between 2000 and 2007 from the linked Surveillance, Epidemiology, and End Results (SEER) and Medicare dataset. Pts surviving at least 30 days post-diagnosis were identified and followed until death or censoring in December 2009. Pathologic fracture, spinal cord compression, and bone surgery were identified from Medicare claims based on three measures: 1) SRE claim occurred after claims with a bone metastasis (BM) ICD 9 code; 2) BM ICD 9 code directly coincided with SRE claim; 3) SRE was not anchored to BM. Cox proportional hazards regression models controlled for demographic and clinical factors, including interaction terms involving indicators for comorbidities. Regression models were estimated using all-cause and PCa-specific mortality as outcomes. Results: Application of inclusion/exclusion criteria resulted in 7,062 pts. PCa-specific and all-cause mortality were 54% and 80% at a median (mean; min; max) follow up of 609 days (837; 30; 3,653). The proportion with any SRE was 17% (Measure 1), 9.7% (Measure 2), and 17.1% (Measure 3). Joint tests indicated statistically significant interaction terms using Measure 1 for PCa-specific mortality and Measure 3 for all-cause mortality. The adjusted hazard ratio (AHR) and 95% confidence interval (CI) on the SRE indicators are shown in the Table. Conclusions: The association between SREs and death among elderly M1 PCa patients is affected by comorbidities. [Table: see text]