Endoscopic Resection for Small Rectal Neuroendocrine Tumors

A transparent cap with an inner groove (MH-593; Olympus, Tokyo, Japan) was attached to the forward-viewing colonoscope. After the endoscope was inserted into the rectum, a crescent-shaped electrosurgical snare was passed through the sheath and looped along the inner groove of the cap. Submucosal injections were not required in this method. The tumor was suctioned into the cap and grasped by tightening the snare. After confirming the appropriate snare placement, both the tumor and overlying mucosa were resected using electric cautery (Endocut Q, effect 2, VIO 200D; ERBE, Tübingen, Germany), and the resected tumor was sent for pathological examination. Endoscopic examination was repeated without a transparent cap to evaluate the wound carefully in cases of perforation or bleeding and to ensure the absence of residual tumor tissues. If there was spurting or active bleeding, hot forceps were used to stop the bleeding.

ESD was performed as the standard procedure and has been widely described and used. First, dots were marked approximately 5 mm from the periphery of the lesion using coagulation. Subsequently, a diluted sodium hyaluronate solution with indigo carmine dye was injected submucosally. Mucosal incision and submucosal dissection were performed using a T-Type ESD Knife (Micro-Tech, Nanjing, China) or Dual-knife (Olympus Medical, Tokyo, Japan). After resection was completed, all visible vessels on the artificial wound were thoroughly coagulated to prevent postoperative bleeding.