Neuroendocrine tumors of the appendix in children and adolescents

Neuroendocrine tumors (NET) of the appendix in children and adolescents are rare and mostly detected postoperatively by a histopathological examination. Since the malignant potential of these tumors remains unclear, therapeutic recommendations are not evidence based. The Society of Pediatric Oncology and Hematology (GPOH) has prospectively registered and followed children with appendical NET since 1997 (GPOH-MET trial). The objective of this study was to critically evaluate the therapeutic recommendations for appendical NET in children.

Clinical data of 237 children with appendical NET were prospectively analyzed.

The mean age at presentation was 13.0 years, while the mean follow-up time was 2.9 (0.0-12.8) years. The majority of tumors (70.9%) were located at the apex, and were smaller than or equal to 10 mm (72.7%). Tumor size was directly correlated with age. A second operation or primary lymph node sampling was done in 25.3% (N = 60) of the patients, and infiltration of the lymph nodes by tumor cells was found in nine of these patients (15%). All 237 patients are alive without tumor symptoms.

ROC analysis and subsequent calculations identified a tumor size of >15 mm as the optimal cut-off point for the prediction of metastatic spread into the lymph system, with a sensitivity of 77.8% and a specificity of 66.7%. Therefore, secondary right hemicolectomy in completely removed appendical NET is recommended only in tumors >15 mm in size. For incompletely removed tumors ≤15 mm a local follow-up resection with lymph node sampling is recommended.