Epidemiology and treatment of high-grade gastrointestinal neuroendocrine tumors (HG-GI-NETs).

Abstract

421 Background: High grade neuroendocrine tumors of the gastrointestinal tract are rare tumors. Management strategies are modeled after small cell lung cancer (SCLC). Treatment patterns and outcomes have not been studied. Methods: Data were obtained from all US hospitals that contributed to the National Cancer Database (NCDB) between 2004 and 2013. Univariate and multivariate testing was done to identify factors associated with patient outcome. Kaplan-Meier analysis and Cox proportional hazards models were used to assess the association between patient characteristics and survival. Results: A total of 1,861 patients were identified for the 10 years of the study. The mean age was 63 years (SD±13), with a male preponderance (53.3%). The vast majority of patients (78.1%) were non-Hispanic Whites. The most common primary sites were pancreas (PNET = 19.4%), large intestine (18.1%), esophagus (17.8%) and rectum (15.5%). About 27.9% of the cases were resectable at the time of diagnosis, and distribution across stages 1-IV was 6.6%, 10.5%, 18% and 64.6% consecutively. Liver was a common site of metastases (50.4%), followed by bone (11.3%) and lungs (10.8%). Only 3.5% of the patients had brain metastases. On univariable analysis, age < 65years (HR 0.72; 0.66-0.8; p < 0.001) and treatment at an academic center (HR 0.88; 0.79-0.99; p < 0.034) were associated with improved survival. Multivariable analysis confirmed prognostic advantage of treatment at an academic center. Patients treated with chemotherapy had a median overall survival (OS) of 11.2 months, compared with 1.7 months for those who did not. The median OS for high grade PNET was 6 months, compared to 9.9 months for other HG-GI-NETs. One year and 5-year survival rates were 27.5% vs. 41% and 4.5% vs. 12.3% respectively. Conclusions: This is the largest series of HG-GI-NET. Almost two-thirds of the cases present with metastatic disease. Pattern of metastasis differs from SCLC. Survival is short. Treatment at high volume academic center, younger age and use of chemotherapy are associated with improved survival.