Pediatric Neuroendocrine Tumors in Denmark: Incidence, Management, and Outcome from 1995 to 2020.

Abstract

Background: Neuroendocrine tumors (NETs), although rare, are considered one of the most common gastrointestinal and bronchopulmonary pediatric neoplasms. We aimed to determine the incidence, tumor characteristics, management, and outcome of NETs and explore the role of genetic predisposition, focusing on low and intermediate grade tumors.

Methods: Using the Danish National Pathology Registry, we conducted a nationwide retrospective study including all Danish children aged ≤18 years diagnosed with a pathology-proven NET between 1995 and 2020.

Results: We identified 220 patients, with a 1.89:1 female to male ratio. The yearly incidence was 6.84 per 1 million children, with no significant change in incidence throughout the observation period. NETs were located in the appendix (93.2%), the pulmonary system (4.5%), and pancreas (2.3%). One recurrence was noted in the pancreas in a genetically predisposed patient with multiple neuroendocrine neoplasia type 1 (MEN1), resulting in an overall recurrence rate of 0.5% (0% in appendiceal NETs; 0% in bronchopulmonary NETs; 20.0% in pancreatic NETs). No NET-related mortality was registered. Four patients had a known predisposing genetic condition, one appendiceal NET associated with neurofibromatosis type 1, and three pancreatic NETs associated with MEN1. Postsurgical surveillance regimes, choice of tumor markers, and imaging modality varied throughout the study period.

Conclusions: We confirmed a stable incidence of pediatric NETs during the study period. The overall recurrence rate was 0.5% and no NET-related mortality was observed. Known genetic predisposition was present in 1.8% of patients. Future guidelines should consider the apparent indolent nature and excellent prognosis of these tumors.