Surgical treatment of gastric neuroendocrine neoplasms

Abstract

Neuroendocrine neoplasms (NEN) are rare neoplasms originating from all major systems, in which gastric neuroendocrine neoplasms (G-NEN) is rarely malignant neoplasm originated in stomach. In 2019, the 5th WHO classification of digestive system tumors updated the classification of G-NEN and solved several naming problems. Since the classification of G-NEN has become more specific and more scientific, the surgical treatment of G-NEN is becoming more individual and more precise. Generally, endoscopic resection is often recommended for the treatment of type I gastric neuroendocrine tumors (NET). Type II gastric NET is mostly secondary to gastrinoma originating from the duodenum or pancreas, and thus surgical treatment of primary gastrinoma deserves enough attention. The decision of operation for type III gastric NET needs comprehensive consideration of tumor size, invasive depth and lymph node metastasis. For gastric neuroendocrine carcinomas without distant metastasis, aggressive surgery should be performed, and the resection range of primary site and lymph nodes can refer to the standard of gastric adenocarcinoma. For locally advanced gastric NEC, it has not been reported whether neoadjuvant chemotherapy or neoadjuvant chemoradiotherapy could reduce tumor stage and improve radical resection rate. In addition, for functional gastric NEN with distant metastasis, radical resection or palliative surgery can be performed to control hormone secretion and may improve the survival. In general, it is an important principle to thoroughly consider biological behavior, extent of primary and metastatic sites, resectability and function of tumor before surgery of gastric neuroendocrine neoplasm, and thus multi-disciplinary treatment (MDT) is recommended.