Knife-assisted full-thickness resection guided by pocket detection method for detection and complete excision of posterior deeply invasive rectal cancer: a novel endoscopic approach

Aims Histologically complete (R0) resection rates using endoscopic submucosal dissection (ESD) for lesions with deep submucosal invasion are suboptimal (62%–64% for Sm 2-3), even in expert centers¹. Currently available techniques for the local resection of deeply invasive rectal cancer include Transanal Minimally Invasive Surgery (TAMIS), endoscopic device-assisted full-thickness resection (FTRD)² and endoscopic intermuscular dissection (EID)³. These techniques have limitations in specific situations such as lesion size, location, or poor ability to delineate margins. We aimed to demonstrate the safety and feasibility of tunnelling knife-assisted full-thickness resection (kFTR) for the detection and excision of deeply invasive rectal cancer.

Methods Consecutive lesions on the posterior rectal wall with suspicion of deep submucosal invasion on magnification chromoendoscopy and/or magnetic resonance imaging/endoscopic ultrasound were retrospectively included. Knife-assisted full-thickness resections (kFTR) were performed at a tertiary centre for interventional endoscopy, between February and May 2024 by a single operator with extensive experience (> 500 ESDs as the first operator). A multidisciplinary team (MDT) discussed the cases and agreed on endoscopic resection due to patient preference or unsuitability for surgery due to comorbidities and/or advanced age. kFTR guided by pocket detection method involved creating a submucosal (SM) pocket to detect and isolate the lesion's predicted deeply SM-invasive component, followed by circumferential muscularis propria incision around the SM-invasive component, dissection, and clip closure [1] [2] [3].

Results Three patients with posterior rectal lesions suspicious of deeply invasive cancer underwent kFTR. Technical success, accuracy of detecting deep SM-invasion, and en-bloc resection rates were 100%. Median procedure time was 113 [IQR 50.0] minutes and and the median dissection speed was 14.0 mm²/min [IQR 1.8] for a median area dissected of 1220.4 [IQR 736.0] mm². The median hospitalization was 1 [IQR 0.5] day. No peri- or post-procedural adverse events occurred. Histopathology showed R1-vertical resection in patient 1 (pT2 adenocarcinoma) and R0 resection in patients 2 and 3 (both pT1bsm3) after refinement of the procedure to include a≥3mm muscularis propria margin. There was no recurrence at the first endoscopic follow-up of patients 1 and 2.

Conclusions Knife-assisted full-thickness resection guided by pocket detection method may be a feasible and safe organ-preserving option for the detection and resection of posterior deeply invasive rectal cancer.

Publikationsverlauf

Artikel online veröffentlicht:
27. März 2025

• References

• 1 Watanabe D, Toyonaga T, Ooi M. et al. Clinical outcomes of deep invasive submucosal colorectal cancer after ESD. Surg Endosc 2018; 32: 2123-2130
• 2 Moons LMG, Bastiaansen BAJ, Richir MC. et al. Endoscopic intermuscular dissection for deep submucosal invasive cancer in the rectum: a new endoscopic approach. Endoscopy 2022; 54: 993-998
• 3 Dolan RD, Bazarbashi AN, McCarty TR. et al. Endoscopic full-thickness resection of colorectal lesions: a systematic review and meta-analysis. Gastrointest Endosc 2022; 95: 216-224.e18