Unicentric retrospective study of gastroenteropancreatic neuroendocrine tumors: Updated epidemiological insights

Neuroendocrine neoplasms (NENs) are rare tumors, making up 0.5 % of all cancers, with around 65 % found in the gastroenteropancreatic (GEP) system, with increasing occurrence globally in recent years. The World Health Organization (WHO) classifies GEP-NENs into two main groups: neuroendocrine tumors and neuroendocrine carcinomas according to the new 2022 classification.

To provide updated epidemiological data on GEP-NENs diagnosed at a tertiary referral center in Beirut, Lebanon, using the WHO 2022 classification, and to describe changes in incidence, demographics, and tumor characteristics compared with previously reported data.

This retrospective study included patients treated at Hotel Dieu de France, from January 2013 to June 2024, with histologically confirmed GEP-NENs and complete medical records available. GEP-NENs were categorized based on their primary site and pathology reports reanalyzed according to the WHO 2022 classification. Data were then collected on patient demographics, primary tumor site, tumor grade and presence of metastasis at diagnosis.

Among 194 NENs diagnosed during the study period, 74 were GEP-NENs (25.2 %). The mean age at diagnosis was 59.8 years, with a male-to-female ratio of 1.61. Of patients with available grading data, 39.0 % were classified as NET G1, 34.4 % as NET G2, and 26.6 % as high-grade disease (NET G3 and NEC combined). Compared with data from the previous decade, a lower proportion of G1 tumors and higher proportions of G2 and G3 tumors were observed, along with higher frequencies of pancreatic and hepatic primaries and lower rates of colonic and duodenal primaries. NET G3 and NECs were most frequently located in the liver, ampulla of Vater, and colon. All colorectal GEP-NENs identified were metastatic at diagnosis.

GEP-NENs in this cohort were more frequently diagnosed with higher histological grades and metastatic disease compared to the previous decade, a pattern observed during a period marked by major socioeconomic disruption and the COVID-19 pandemic.