Long-term outcomes and prognostic factors in neuroendocrine carcinomas of the pancreas: Morphology matters

Background Limited data are available for pancreatic neuroendocrine carcinomas (NEC) defined by 2010 World Health Organization (WHO) criteria (mitotic count >20 mitoses/10 high-power fields and/or a Ki67 index of >20%), because most studies encompass heterogeneous cohorts of extrapulmonary/gastrointestinal NEC. Our aim was to evaluate the clinicopathologic characteristics, treatment, and prognosis of patients with pancreatic NEC defined by the 2010 WHO criteria. Methods We conducted a retrospective analysis of 59 patients with a histologic diagnosis of NEC between 1990 and 2012. All cases were re-reviewed and classified according to the WHO 2010 classification and the WHO 2000 criteria. Results All patients had stage III pancreatic NEC (n = 34; 58%) or IV pancreatic NEC (n = 25; 43%). Overall, 49 (83%) had poorly differentiated (PD) and 10 (17%) had a well-differentiated (WD) morphology. Fifteen patients (26%) were operated with curative intent (R0/R1), and 8 (14%) were R2 resections. Median disease-specific survival (DSS) for the entire cohort was 14 months. Median DSS did not differ between patient not undergoing resection and those undergoing R2 resection (10 vs 12 months; P >.46), but DSS was greater for patients who underwent R0/R1 resection compared with those with no resection/R2 resection (35 vs 11 months; P <.005). WD morphologic NEC had a greater survival than PD ones (43 vs 12 months; P =.004). Performance status, R2 resection/no resection, PD morphologic NEC, and no medical treatment were independent predictors of poor survival. Conclusion Pancreatic NEC constitute a heterogeneous group of tumors. Although NEC is an aggressive disease, curative resection in localized disease is associated with improved survival. Morphologic WD pancreatic NEC represents a subgroup with what seems to be a markedly improved survival. Within the NEC category, tumor treatment should be individualized considering tumor morphology as well as the other 2010 WHO criteria.