Effect of treatment center volume on outcomes in gastroenteropancreatic neuroendocrine tumor patients.

Abstract

502 Background: Gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are relatively rare tumors, where patients seek care at medical centers with varying levels of expertise. While treatment center volume is associated with better survival in multiple cancers, it remains unknown whether the same applies to GEP-NETs. The objective of this study was to assess the impact of center volume on GEP-NET treatment outcomes. Methods: We used the Surveillance, Epidemiology, and End Results (SEER) registry linked to Medicare claims data in this study. We included patients diagnosed between 1995-2010 who had no HMO coverage, participated in Medicare parts A and B, were older than 65 at diagnosis, had full tumor grade information, and had no secondary cancer. We used Medicare claims to identify the medical centers at which patients received GEP-NET treatment (surgery, chemotherapy, somatostatin analogues, or radiation therapy). Center volume was divided into tiers – low, medium, and high – based on the number of unique GEP-NET patients treated by a medical center over two years. Kaplan-Meier curves and Cox regression were used to assess the association between volume and disease-specific survival (DSS). Results: We identified 1025 GEP-NET patients, of whom 65%, 28%, and 7% received treatment at low, medium, and high volume centers, respectively. Surgery was the most common first treatment (84-90%). Comorbidity and tumor stage distribution were similar across tiers, but the distribution of patients with poorly-differentiated tumors differed significantly (p < 0.001). Median DSS for patients at low and medium centers were 3.7 years and 6.6 years, respectively, but was not reached for patients at high volume centers. After adjusting for confounders, patients treated at high volume centers had better survival than those treated in low volume centers (HR: 0.55, 95% CI: 0.30-0.99). However, no difference in survival was noted at medium volume centers (HR: 0.98, 95% CI: 0.78-1.22). Conclusions: Our results suggest that centers with expertise in GEP-NET treatment have better patient outcomes. Thus, centralization of care, particularly of more difficult cases, may lead to improved patient outcomes.