Endoscopic treatment of rectal neuroendocrine tumors in a 13-year retrospective single-center study: are we following the guidelines?

Introduction: Rectal neuroendocrine neoplasms (rNENs) are potentially metastatic lesions. False endoscopic diagnosis and subsequent treatment may lead to nonradical resection and metastases.

Objectives: This study aimed to analyze the clinical characteristics of rNENs, investigate whether the lesion origin was suspected by endoscopists during examination and if those lesions were subsequently removed using the appropriate method, and assess the outcomes of patients after curative and noncurative resections.

Patients And Methods: We analyzed the records of patients hospitalized in our department (2006-2019) with a diagnosis of rNENs. We included 40 patients with rNENs, evaluated their clinical characteristics, and investigated whether the neuroendocrine origin of the lesions was suspected on endoscopy. We compared the outcomes of patients treated with the proper method (endoscopic submucosal dissection / endoscopic mucosal resection [ESD / EMR]) and those treated with polypectomy.

Results: Abnormalities appeared as typical, yellowish subepithelial lesions (n = 24), lesions resembling hyperplastic polyps (n = 12), or tumors with central depression (n = 4). The median size was 5.5 mm and most of them were G1 lesions (n = 36). Only 14 of them were suspected to be of neuroendocrine origin at the first endoscopic examination, and 12 were removed by ESD / EMR. The remaining tumors (n = 26) were removed using polypectomy. Most of the patients were disease‑free at follow‑up, but 2 patients after polypectomy and a single patient after nonradical ESD developed metastases.

Conclusion: In most cases, the origin of the lesion was not suspected on colonoscopy and subsequently the tumor was removed using an inappropriate method. Endoscopists do not follow the guidelines when dealing with patients with rNENs and more emphasis should be placed on education on the management of rNENs.