Variation in patterns of health care and survival among patients with brain metastases in the VHA health system.

Abstract

204 Background: Brain metastases (BM) occur in approximately 15-25% of patients with advanced primary cancers and cause significant morbidity and mortality. This study examines the variation in patterns of healthcare and survival among patients with brain metastases in the US veterans’ population. Methods: A retrospective cohort design identified BM patients, divided into 5 most prevalent primary cancer cohorts using claims and enrollment data (10/1/2005 - 5/31/2012) from the Veterans Health Administration (VHA), the largest integrated health care system in US. Inclusion required ≥ 2 diagnoses of BM (ICD-9 code 198.3x) separated by ≥ 7 days with 1 primary cancer diagnosed before BM. The different BM cohorts were compared to the cohort with the highest prevalence of a primary cancer for the following outcomes: median survival (Kaplan-Meier estimates), per patient month (PPM) rate of healthcare utilization, baseline comorbidities, and use of brain-directed and supportive treatments. Results: Study sample consisted 4,393 BM patients (mean age of 65.6 years, 97% male), divided into 5 most prevalent primary cancer cohorts - 2,783 lung cancer, 574 skin, 568 prostate, 236 kidney, and 232 colorectal cancer patients. Median time to death after BM diagnosis was 103 days for lung, compared to 84 (p<0.01) for skin, and 127, 109, 99 days (all p>0.05) for kidney, prostate and colorectal cohorts respectively. Patients with ≥3 comorbidities ranged from 50% (skin) to 62% (colorectal). Compared to lung, the kidney cohort reported higher emergency room visits (21.6% vs. 16.3%, p=0.04), prostate and colorectal cohorts reported higher inpatient visits (65.3%, 69.4% vs. 59.6%, p=0.011, 0.003, respectively). Whole brain radiotherapy was the most common brain-directed treatment, ranging from 24% (kidney) to 37% (lung); brain-surgery ranged from 7% (lung) to 10% (colorectal); 89% to 94% used corticosteroid supportive therapy. Conclusions: High unmet need exists in the brain metastases population in terms of poor survival, high comorbidity burden and significant healthcare resource utilization. Patient outcomes vary significantly by primary cancer sites reflecting the heterogeneity of this disease.