Introduction
During endoscopic submucosal dissection (ESD) of colorectal neoplasms, an interesting feature is occasionally detected in which the muscle layer under the tumour seems to be pulled upwards into the lesion in a triangle-shape. This feature is named muscle retracting sign (MR sign) and appears to indicate a potentially difficult ESD with high risk of incomplete and non-curative resection, although data about this subject is still scarce, without current studies in western countries. The aim of this study was to evaluate whether or not MR sign is associated with worst outcomes.
Aims & Methods
A retrospective analysis, using a prospectively collected database from 2 western centres, including all patients who underwent ESD for colorectal neoplasms with positivity for MR sign from July 2017 to January 2023 was performed. The presence of MR sign was determined by the endoscopist during the procedure. The results were evaluated in terms of complete, en bloc, R0 and curative resection rates, complications and local recurrence.
Results
In a total of 411 lesions treated by ESD, 26 presented MR sign (6.3%, mean size 62,3mm, range 20-180mm): 9 colonic and 17 rectal, corresponding to 26 patients (male 61.5%, mean age 70 years): 9 in colon and 17 in rectum. Morphologically and according to Paris classification, 13 were 0-Is (50%), 10 LST-G-M (38.5%), 1 0-Isp, 1 LST-G-N and 1 LST-NG-F. Technical success was achieved in 24 lesions (24/26, 92.3%) with 2 procedures aborted due to the perception of high perforation risk, both located in the colon (2/9, 22%). In the rectum, there was the need to perform intramuscular dissection in 3 procedures to complete the resection (3/17, 17.6%). Among resected lesions, en bloc and R0 resection rates were 100% and 66.7% (16/24). According to ESGE 2022 criteria, resection was considered curative in 66.7% (16/24), non-curative with high risk in 8.3% (2/24) and with local-risk recurrence in 25% (6/24). Intraprocedure complications were recorded in 2 resections (8%), both in the rectum and both perforations endoscopically managed. No recurrence was recorded in a mean follow-up time of 7 months (range 1-22 months).
Conclusion
This analysis show that MR sign is mostly present in large bulky protruding lesions and seems associated with a higher incomplete resection procedure rate in colon lesions but in rectum. Also, it seems associated with higher complication rate, namely perforations, and non-curative resection rates among resected lesions. Therefore, in the colon, an anticipated switch for surgery in clinically fit patients should be considered in the presence of this sign or even before initiating ESD when lesion morphology suggests its presence. To the authors’ best knowledge, this is the first study of the impact of the present of MRS in ESD in the West.
References
Toyonaga T, Tanaka S, Man-I M, East J, Ono W, Nishino E, et al. Clinical significance of the muscle-retracting sign during colorectal endoscopic submucosal dissection. Endosc Int Open. 2015;3(03):E246–51.
Suzuki N, Dhillon A, Seward E, Humphries A. CLIP MUSCLE PROTECTION (CLIMP) METHOD IN MUSCLE-RETRACTING SIGN DURING COLONIC ENDOSCOPIC SUBMUCOSAL DISSECTION. Gut. 2021;70(Suppl 1):A1–A262.
Disclosure
Toyonaga T, Tanaka S, Man-I M, East J, Ono W, Nishino E, et al. Clinical significance of the muscle-retracting sign during colorectal endoscopic submucosal dissection. Endosc Int Open. 2015;3(03):E246–51.