Long-term outcomes of transanal endoscopic microsurgery for the treatment of rectal neuroendocrine tumors

Abstract

Background Transanal endoscopic microsurgery (TEM) has been accepted worldwide for the treatment of local rectal lesions. We aimed to assess the efficacy and safety of TEM in the treatment of rectal neuroendocrine tumors (RNET). Methods A retrospective study of patients who had undergone TEM for RNET at our institution between December 2006 and June 2019 was performed. Demographic and tumor characteristics, operative and pathological details, complications, anal function questionnaires, and follow-up data were included. Results A total of 144 patients was included. TEM was performed as primary excision in 54 patients, after endoscopic forceps biopsy in 57 patients, and after incomplete resection by endoscopic excision in 33 patients. The median size of all primary tumors was 0.6 cm (range, 0.3–2.0 cm), and the negative resection margin was achieved in 142 (98.6%) patients. Postoperative complications (referring to only bleeding) occurred in 3 (2.1%) patients and was successfully managed with conservative method. After a median follow-up of 75.5 months after surgery, 3 patients died of other causes, and 2 patients suffered metastasis. An anal function questionnaire was posted 24 months after TEM. Among the results, 3 (2.1%) patients complained of major low anterior resection syndrome (LARS), including 1 (0.7%) who suffered from complete incontinence, while 6 (4.2%) patients had minor LARS. Conclusions TEM has satisfying long-term outcomes and relatively low anal function disturbance as for the treatment of small RNET. TEM also acts as a preferred salvage treatment for incomplete endoscopic excision.

European Neuroendocrine Tumor Society (ENETS) 2023 guidance paper for colorectal neuroendocrine tumours

“…Below the size of 1 cm an experienced endoscopist will be able to determine whether it is likely that an R0 resection can be achieved, and then it is reasonable to use at least a lifting or a cap technique to remove the lesion. 52 A meta-analysis showed that ESD was successful for rectal NEN with a complete resection rate of 89%, 4% adverse events and <1% local recurrence. The complete resection rate was better for ESD than for conventional EMR (89 vs. 75%, p < .001).…”

“…The doughnut appearance commonly occurs when the lesion reaches 1 cm. Below the size of 1 cm an experienced endoscopist will be able to determine whether it is likely that an R0 resection can be achieved, and then it is reasonable to use at least a lifting or a cap technique to remove the lesion 52 …”

Treatment of localized well-differentiated rectal neuroendocrine tumors: A focused review

“…The advantage is that full-thickness resection is possible, and safe surgical outcomes have been reported, including in those with large tumor diameters. [82,83] Although there are few studies comparing between transanal surgery and endoscopic treatment, retrospective studies have shown that ESD and endoscopic full-thickness resection are associated with fewer adverse events and shorter operating time and hospital stay than is transanal surgery for tumors measuring ≤10 mm. [84,85]…”