Review of endoscopic diagnosis and management of small rectal neuroendocrine tumours in a tertiary centre

Introduction The incidence of neuroendocrine tumours (NETs) is increasing with a heightened awareness of the malignant potential of rectal NETs. There is a need to improve the endoscopic recognition of NETs at earlier stages but there is a lack of data to compare the available endoscopic interventions. Methods A review was undertaken using a prospectively collected database of all patients undergoing endoscopic treatment for rectal NETs between January 2010 and January 2019. Demographics and procedural data including histology reports were retrieved and reviewed. Results 24 patients (10 female; median age 56 [range 33–73]) underwent endoscopic treatment for 24 rectal NETs. The median size, estimated during endoscopy was 5 mm (range 2–15 mm). Ten NETs (42%) were incidentally detected at bowel cancer screening procedures. During index procedures, 7 (29%) lesions were correctly described as submucosal tumours (SMT) and 3 (12%) as NETs. The remaining 14 (59%) were described as polyps. Biopsies were taken in 15 cases, of which histological diagnosis was made in 12/15 (80%). The 3 remaining biopsies were reported as normal colonic mucosa. Endoscopic therapy was attempted during 14 index procedures; cold biopsy (5), hot snare (3), endoscopic mucosal resection (EMR) (6). All 14 NETs were incompletely resected (R1) and subsequently had ESD as definitive therapy (R0). In 2 cases EMR was attempted as definitive therapy following index procedure, however also required subsequent ESD to achieve R0 resection. The 8 remaining NETs were successfully resected (R0) with endoscopic submucosal dissection (ESD) (7) or ligation-assisted EMR (Duette® Multi-Band Mucosectomy device, Cook Medical Ltd) (1). All patients were referred to the surgical NET specialist team for ongoing management and monitoring. Surveillance endoscopy has been performed in 18 patients (median 16.5 months [range 6–81]) with no endoscopic evidence of recurrence. Conclusions Ten (42%) rectal NETs were discovered early due to bowel cancer screening programs. Endoscopic recognition of SMTs can be improved by confirming a type 1 Kudo pit pattern and firmness to palpation. With careful endoscopic assessment of SMTs, biopsies were not essential for diagnosis, despite a high positive rate. We recommend biopsying suspected lesions if unsure. Small rectal NETs should be treated with either ESD or ligation-assisted EMR for complete resection.