[Report on the application of endoscopic intermuscular dissection for diagnostic resection of early rectal cancer].

Objective: This report presents the initial outcomes of endoscopic intermuscular dissection (EID), a novel technique introduced by our team for the diagnostic resection of early rectal cancer, focusing on the postoperative status of the vertical margins. Methods: On January 26, 2024, a patient with early rectal cancer (cT1-2N0M0) underwent Endoscopic Intermuscular Dissection. The EID procedure consists of six steps: (1) mucosal incision; (2) submucosal dissection; (3) superficial muscular layer incision; (4) intermuscular dissection; (5) complete tumor removal; (6) wound management. Results: The patient was a 70-year-old male with rectal cancer (cT1-2N0M0). The tumor was located on the left anterior wall of the rectum, approximately 9 cm from the anal margin, and measured 20mm in size. The dissection rate was 2.68 mm²/minute, and the total duration of the surgery was 109 minutes. The patient was successfully discharged on the fifth day after surgery. Pathological examination of the post-endoscopic surgery specimen revealed pT1b, with negative vertical margins. Follow-up after more than one month showed good recovery with no complications such as bleeding, perforation, infection, or stricture occurring. Colonoscopy indicated the presence of a granulation tissue suggestive of inflammation. Conclusion: Endoscopic Intermuscular Dissection for the diagnostic resection of early rectal cancer is potentially safe and may achieve negative vertical margins.