Management of rectal neuroendocrine tumours by transanal endoscopic microsurgery.

[AIM] The objective of this study was to evaluate the safety and effectiveness of transanal endoscopic microsurgery for rectal neuroendocrine tumours.

[METHOD] A retrospective cohort study of all pathology-confirmed rectal neuroendocrine tumours treated by transanal endoscopic microsurgery from April 2007 to December 2020 at a tertiary care centre was performed. Demographic, clinical, radiographic and pathological data were collected. Characteristics of patients with recurrence were examined. Descriptive statistics were performed.

[RESULTS] There were 58 patients treated by transanal endoscopic microsurgery excision. Referrals were for primary excision (15, 25.9%), completion re-excision after incomplete endoscopic removal (38, 65.5%) or locally recurrent rectal neuroendocrine tumours (5, 8.6%). The mean age of patients was 56.4 ± 11.9 years and 26 patients were women (44.8%). Mean tumour size was 7.4 ± 3.8 mm (range 1.0-15.0 mm). Most (86.4%) were Grade 1 tumours. Mean operative time was 37.2 ± 17.2 min and 56 patients (96.6%) were discharged on the same day. All patients had negative margins on final pathology. Of the 38 patients who were referred for completion re-excision after incomplete endoscopic removal, eight (21.1%) had residual tumour on final pathology. Three recurrences were diagnosed at 2.1, 4.5 and 12.5 years after excision. All recurrences were from Grade 1 or 2 primary tumours, less than 2 cm, and diagnosed radiographically.

[CONCLUSION] To date, this is the largest North American study looking at transanal endoscopic microsurgery for rectal neuroendocrine tumours. This technique is effective in managing primary, incompletely excised and recurrent tumours with good clinical and oncological outcomes.