Treatment Response and Outcomes of Grade 3 Pancreatic Neuroendocrine Neoplasms Based on Morphology: Well Differentiated Versus Poorly Differentiated.

OBJECTIVES

Emerging data suggest that not all grade 3 (G3) pancreatic neuroendocrine neoplasms (panNENs) behave the same; tumor differentiation may predict outcome.

METHODS

Patients with G3 panNENs treated at our institution between 1999 and 2014 were identified. Demographics, response to therapy, and overall survival were determined.

RESULTS

Forty-five patients were identified, 16 with G3 well differentiated pancreatic neuroendocrine tumors (WD-panNETs) and 29 with poorly differentiated neuroendocrine carcinomas (PDNEC). Median overall survival in G3 WD-panNET patients was 52.2 months (95% confidence interval, 19.3-86.9 months) compared with 10.1 months (95% confidence interval, 6.9-12.4 months) in PDNEC patients (P = 0.0009). Response rate to platinum agents was 10% in G3 WD-panNETs and 37% in PDNEC. Response rate to alkylating agents was 50% in G3 WD-panNETs and 50% in PDNEC.

CONCLUSIONS

Both G3 WD-panNETs and PDNEC responded to platinum and alkylating agents. Overall survival was significantly greater in G3 WD-panNETs compared with PDNEC. These findings challenge current classification and suggest that G3 panNENs should be classified by morphology.