Long-term outcomes according to additional treatments after endoscopic resection for rectal small neuroendocrine tumors

Abstract

The present study aimed to investigate treatment strategies determining additional treatment after endoscopic resection (ER) of rectal neuroendocrine tumor (NET)s and long-term outcomes of endoscopically resected rectal NETs. We analyzed a total of 322 patients medical records of patients who underwent ER for rectal NETs. Rectal NETs initially resected as polyps and treated with conventional endoscopic mucosal resection (EMR) were observed more frequently in the non-curative group (P = 0.041 and P = 0.012, respectively). After ER, only 44 of the 142 patients (31.0%) who did not meet the criteria for curative resection received additional salvage treatment. In multivariate analysis, lesions diagnosed via biopsies (OR, 0.096; P = 0.002) or suspected as NETs initially (OR, 0.04; P = 0.001) were less likely to undergo additional treatment. Positive lymphovascular invasion (OR 61.971; P < 0.001), positive (OR 75.993; P < 0.001), or indeterminate (OR 13.203; P = 0.001) resection margins were more likely to undergo additional treatment. Although lymph node metastasis was found in 6 patients, none experienced local or metastatic tumor recurrence during the median follow-up of 40.49 months. Long-term outcomes after ER for rectal NETs were excellent. The prognosis showed favorable outcomes regardless of whether patients receive additional salvage treatments.

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

“…However, endoscopic resections have yet to prove their effectiveness (R0 resection) and safety; previous reports concerning the management of small r-NETs remain limited to several single-institution retrospective studies with a small number of cases, and large Asian studies where the epidemiology of r-NETs, endoscopic expertise and health services are different to those of Western countries. [4][5][6][7][8][9][10][11] We therefore conducted a large multicentre nationwide study in France to evaluate the outcomes of non-metastatic r-NETs 2 cm in size diagnosed endoscopically. The primary objective was to describe the proportion of R0 resection.…”

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

“…The key issue in the initial management of these lesions is to suspect rectal NEN based on macroscopic features before mistakenly performing routine snare polypectomy. A retrospective analysis by Lee et al [11] showed that it was possible to suspect a NET by macroscopic appearance, on endoscopy, in 95.9% of cases (94/98 lesions) [12]. These tumours are also described as hard and movable, and some authors suggested checking these features with a biopsy forceps as a helpful diagnostic tool [12].…”

“…However, the evidence supporting this management is not very strong due to the lack of large comparative studies comparing the outcomes of patients after non-curative endoscopic resection who did not undergo adjunct therapy and those who underwent salvage treatment. Cha et al followed up a group of 322 patients who underwent endoscopic resection of rNENs and found that only 31% (44/142) of the patients who did not fulfil the criteria of R0 resection underwent salvage therapy [11]. Eleven of these patients underwent surgery, and lymph node metastases were found in six patients, while there were no features of disease progression in the remaining patients [11].…”

“…Cha et al followed up a group of 322 patients who underwent endoscopic resection of rNENs and found that only 31% (44/142) of the patients who did not fulfil the criteria of R0 resection underwent salvage therapy [11]. Eleven of these patients underwent surgery, and lymph node metastases were found in six patients, while there were no features of disease progression in the remaining patients [11]. The study by Fine et al in patients with rNENs showed a generally favourable natural history, and recurrence after endoscopic resection was only observed in 5% of cases (16/345) in the EMR-C -cap assisted endoscopic mucosal resection; ESMR-L -endoscopic submucosal resection with a ligation device; LCEMR -endoloop ligation after cap-endoscopic mucosal resection; FTR -full-thickness resection; FTRD -full-thickness resection device…”

“…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]. Herein, we review the key points of endoscopic management, from diagnosis to treatment.…”