The impact of surgery for metastatic pancreatic neuroendocrine tumor: a contemporary evaluation matching for chromogranin a level.

BACKGROUND: Studies supporting surgical management of metastatic pancreatic neuroendocrine tumor (PNET) are limited by selection bias. Chromogranin A (CgA) has been used as a biomarker for PNET and may reflect disease burden or biology. This study aimed to correlate CgA level with overall survival and to use it to match patients selected for different treatment approaches in an analysis of the impact of surgical management. METHODS: 1478 patients diagnosed with PNET in the National Cancer Database (2004-2014) were retrospectively identified, and logistic regression analyses were used to evaluate associations between the presence of metastatic disease and CgA level. After matching patients by CgA level and other factors predictive of surgical management, Kaplan-Meier survival analysis was performed. RESULTS: Median CgA level was significantly higher in metastatic versus localized PNET(169 ng/mL versus 66 ng/mL, p < 0.001). On multivariate logistic regression, CgA level was predictive of metastatic disease(OR 1.002, p < 0.001) and survival in metastatic and non-metastatic patients. After matching for CgA level, surgery was associated with improved overall survival. DISCUSSION: CgA level is predictive of the presence of distant metastatic disease and overall survival in PNET. When matched by CgA and other predictors of treatment approach, patients with metastatic PNET undergoing surgery have improved survival.