Outcomes of small-cell versus large-cell gastroenteropancreatic neuroendocrine carcinomas: A population-based study.

The recent World Health Organization classification for gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) classified poorly differentiated GEP-NENs into small cell and large cell categories. The present study aimed to assess the differences in outcomes between patients with both histological categories. The Surveillance, Epidemiology and End Results (SEER) database (1975-2016) was accessed and patients with small cell and large cell GEP-neuroendocrine carcinomas (NECs) were extracted. Differences in survival outcomes were explored through Kaplan-Meier survival estimates and multivariable Cox regression models. In total, 2204 patients with GEP-NEC were identified in the survival cohort, including 1698 patients with small cell NEC (77%) and 506 patients with large cell NEC (23%). Using Kaplan-Meier analysis/log-rank testing, large cell GEP-NEC was associated with better overall survival compared to small cell NEC (P < 0.01). Using multivariable Cox regression analysis, large cell GEP-NEC was associated with better overall survival (large cell GEP-NEC versus small cell GEP-NEC, hazard ratio = 0.77; 95% confidence interval = 0.68-0.86) and cancer-specific survival (large cell GEP-NEC versus small cell GEP-NEC, hazard ratio = 0.79; 95% 95% confidence interval = 0.69-0.91). Patients with small cell GEP-NEC have worse survival outcomes compared to those with large cell GEP-NEC. Further efforts are needed to identify biological differences and treatment sensitivities between both histological categories.