Overall survival in hormone-resistant prostate cancer patients with different transition of care within the Veterans Affairs (VA) system.

Abstract

5091 Background: Prostate cancer patients with locally advanced /metastatic disease have a poor prognosis and although hormonal therapy can induce long-term remission, development of hormone-resistant prostate cancer (HRPC) is inevitable. The goal of this study is to evaluate overall survival in HRPC patients with different transition of care in the Veterans Affairs (VA) system. We hypothesized that prostate cancer patients with late referral to medical oncologists were more likely to have decreased overall survival. Methods: This is a retrospective, observational analysis of patients enrolled in the Veterans Health Administration system from October 2003 to March 2011. Patients were followed from initial evaluation and treatment by urology until an endpoint of death or the end of the study period. VA patients with a diagnosis of HRPC were identified; prostate specific antigen (PSA), medical and pharmacy records were collected. HRPC was defined as PSA doubling after treatment with hormonal therapy. Transition of care was defined as two encounters with the medical oncology service and at least one encounter was a medical oncologist. Three cohorts were created: patients transitioned to oncology before HRPC, those transitioned to oncology after HRPC, and patients who were never transitioned to oncology. Primary outcome was overall survival (OS). The Charlson score was utilized for comorbidity assessment. Statistical analysis was conducted using chi square test for categorical variables. Results: Total number of patients evaluated was 8,281; 2,168 in transition before HRPC (tbHRPC) cohort, 2,052 in transition after HRPC (taHRPC), and 4,061 patients that never transitioned (tnHPRC). The mean ages for the respective cohorts were: 69.35, 69.69, and 71.64. The Charlson comorbidity scores were 3.79 (tbHRPC), 3.06 (taHRPC), and 3.14 (tnHRPC); p-values < 0.05. Mortality rates among the cohorts were 57% tbHRPC, 69% taHRPC, and 62% tnHRPC; p-values <0.001. PSA doubling within 10 months were: 57% tbHRPC, 60% taHRPC, and 54% tnHRPC; p-values < 0.05. Conclusions: Overall survival was improved among prostate cancer patients that transitioned to oncology before becoming HRPC.