Endoscopic management of 345 small rectal neuroendocrine tumours: A national study from the French group of endocrine tumours (GTE)

Abstract

Introduction Small rectal neuroendocrine tumours are good candidates for endoscopic resection provided that complete pathological resection (R0) is obtained and their risk of metastatic progression is low. We conducted a large multicentre nationwide study to evaluate the outcomes of the management of non-metastatic rectal neuroendocrine tumours ≤2 cm diagnosed endoscopically. Patients and methods The medical records, the endoscopic and pathological findings of patients with non-metastatic rectal neuroendocrine tumours ≤2 cm managed from January 2000–June 2018 in 16 French hospitals, were retrospectively analysed. The primary objective was to describe the proportion of R0 endoscopic resections. Results A total of 329 patients with 345 rectal neuroendocrine tumours were included, 330 (96%) tumours were managed by local treatments: 287 by endoscopy only and 43 by endoscopy followed by transanal endoscopic microsurgery. The final endoscopic R0 rate was 134/345 (39%), which improved from the first endoscopy (54/225, 24%), to the second (60/100, 60%) and the third endoscopy (20/26, 77%). R0 was associated with endoscopic technique (90% for advanced techniques, 40% for mucosectomy and 17% for polypectomy), but not with tumour or patient characteristics. Twenty patients had metastatic disease, which was associated with tumour size ≥10 mm (odds ratio: 9.1, 95% confidence interval (3.5–23.5)), tumour grade G2–G3 (odds ratio: 4.2, (1.5–11.7)), the presence of muscular (odds ratio: ∞, (11.9–∞)) and lymphovascular invasion (odds ratio: 57.2, (5.6–578.9)). Conclusions The resection of small rectal neuroendocrine tumours often requires multiple procedures. Training of endoscopists is necessary in order to better recognise these tumours and to perform the appropriate resection technique.

Endoscopic management of rectal neuroendocrine tumours. How to avoid a mistake and what to do when one is made?

“…median follow-up of 32 months; however, in two cases it led to patient death [10]. This study also revealed that the neuroendocrine origin of the polyps is suspected in a minority of cases on endoscopy, before the polypectomy is conducted, and even when the diagnosis is suspected, many of rNEN are removed with a snare polypectomy, justifying the continuous education of endoscopists in this field [10]. This conclusion is in accordance with the results of our study, which showed that endoscopists suspected polyps of neuroendocrine origin in only 37.5% of cases (9/24 lesions) [9].…”

“…This statement is based on the assumption that the diagnosis is made on endoscopy, and then the patient is referred for treatment, preceded by EUS. Unfortunately, this scenario is far from what occurs in real life, and in many cases, the neuroendocrine origin of the lesion is not suspected on endoscopy and the diagnosis is made retrospectively by a pathologist [10]. In the study by Fine C et al on a large group of 329 patients with small rNEN the suspicion of rNEN on endoscopy was made only in 18% of cases; despite REVIEW this, one third of those that were correctly recognised were removed by polypectomy [10].…”

“…Unfortunately, this scenario is far from what occurs in real life, and in many cases, the neuroendocrine origin of the lesion is not suspected on endoscopy and the diagnosis is made retrospectively by a pathologist [10]. In the study by Fine C et al on a large group of 329 patients with small rNEN the suspicion of rNEN on endoscopy was made only in 18% of cases; despite REVIEW this, one third of those that were correctly recognised were removed by polypectomy [10]. Polypectomy of rectal NENs leads to an unacceptably high incomplete resection rate (69.1-83%) and the risk of a presence of remnant residual tumour [6,7,31,32].…”

“…Recent studies have shown that the majority of lesions are removed by an improper method, even when typical endoscopic features are present, and diagnoses are made retrospectively based on histopathological assessment [9,10]. Thus, there is still a need to educate physicians caring for patients with rNENs, so that accurate diagnoses are made before the "simple" polypectomy (mistake) is done, and to broaden the knowledge of the management after ineffective treatment [11].…”

A small, yellowish nodule in the rectum: not as benign as it seems

“…When radical treatment is applied, the prognosis for rectal G1 NETs with the diameter up to 10 mm is very good, with nearly 100% 5-year survival rate, and these tumors do not even require followup [1]. Unfortunately, in spite of clear recommendations, what is apparent through our patient's story and other studies, is that majority of these lesions are resected with a snare polypectomy [2,3], what may lead to incomplete resection, and subsequently metastatic spread [2][3][4][5]. Moreover, the important factor that led to the fatal outcome was the fact that the patient was lost for follow-up.…”