Optimization of Endoscopic Treatment Strategies for R0 Resection of Rectal Neuroendocrine Tumors Smaller Than 10Mm

Background: The optimal histologically complete (R0) resection methods of endoscopy for rectal neuroendocrine tumor (NET) < 10 mm remains controversial. We aimed to assess the optimal endoscopic treatments for NETs. Methods: The retrospective enrolled patients (n = 208) with rectal NETs were divided into 3 subsets according to pathological tumor size: 2 - 3 mm, 4 - 5 mm, and 6 - 10 mm NETs. Factors associated with R0 resection according to different endoscopic treatments (accidental diagnostic biopsy by cold forceps, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD)) and tumor size were investigated. All patients underwent follow-up and no local recurrence or metastasis were identified. Results: A total of 208 patients were enrolled. In patients with 2 - 3 mm NETs, the R0 resection rate was 100.0 % for biopsy, EMR, and ESD. The R0 resection rate for biopsy of 4 - 5 mm and 6 - 10 mm NETs was 34.3 % and 0.0 % respectively, which was inferior to the EMR/ESD rate (4 - 5mm: p <0.001; 6 - 10 mm: p <0.001: respectively). For patients with < 10 mm NETs, EMR and ESD had a comparable en bloc (p = 0.082) and R0 resection rates (p = 0.651). Conclusion: Accidental diagnostic biopsy by cold forceps could be considered as the possible treatment for 2 - 3 mm rectal NETs. And for patients with < 10 mm rectal NETs, both EMR and ESD might be sufficient.