Clinicopathologic characteristics and survival outcomes of gastroenteropancreatic neuroendocrine neoplasms in Peru: A 15-year retrospective cohort study

Introduction Incidence of gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) has increased globally; however, data from Latin America remain scarce. This study aimed to describe the sociodemographic and clinicopathologic characteristics, treatment modalities, survival outcomes, and prognostic factors of GEP-NENs in a 15-year single-center cohort at a national referral cancer center in Lima, Peru. Materials and methods We conducted a retrospective, hospital-based cohort study. Patients diagnosed with GEP-NENs at the Instituto Nacional de Enfermedades Neoplásicas (INEN) were included from 2009 to 2024, and tumors were classified according to the 2019 WHO Classification of GEP-NENs. Overall survival (OS) was estimated using Kaplan-Meier curves and compared using the log-rank test. Prognostic factors were identified through Cox proportional hazards models. Results Three hundred sixty-eight patients were included. The median age at diagnosis was 57 years, with a female predominance (56.2%). Most patients presented with an ECOG performance status of 0–1 (96.5%), and among patients with available disease-extent information, 64.7% had non-metastatic disease. The majority of tumors were well-differentiated (neuroendocrine tumors [NETs]) (84.2%), while 15.8% were poorly differentiated (neuroendocrine carcinomas [NECs]). The most common primary tumor sites included the rectum (39.1%), stomach (19.8%), and pancreas (18.8%). With a median follow-up of 61.9 months, the 5-year OS rate was 52%. NETs exhibited longer OS than NECs, with 5-year OS rates of 65% and 8%, respectively (log-rank p < 0.001). In the multivariable analysis, metastatic disease (aHR = 2.61, 95% CI: 1.63–4.20; p < 0.001) and poorly differentiated histology (aHR: 4.36, 95% CI: 2.59–7.31; p < 0.001) were independently associated with worse overall survival, whereas surgery (aHR: 0.25, 95% CI: 0.15–0.41; p < 0.001) and systemic treatment (aHR: 0.53, 95% CI: 0.31–0.92; p = 0.024) were associated with improved overall survival. Conclusion Our findings demonstrate that GEP-NENs represent a highly heterogeneous group of neoplasms with substantial variability in clinicopathological characteristics and survival outcomes. Most patients in our cohort had well-differentiated NETs and favorable long-term survival. These findings support the need for comprehensive national registries and multicenter collaborative studies to validate our results and better characterize GEP-NENs in underrepresented Latin American populations.