Is Local Resection of Anal Canal Tumors Feasible with Transanal Endoscopic Surgery?

Background: An important drawback of local surgery for lesions in the anal canal is the difficulty of achieving en bloc full-thickness resections. The aim of this study is to evaluate TEM/TEO in lesions of this type from the point of view of morbidity, mortality and the quality of the pathology specimen. Methods: This is an observational study with prospective data collection from June 2004 to July 2018. Two groups are defined: group A (rectal tumors with proximal margin between 0 and ≤4 cm from anal verge) and group B (distal margin > 4 cm from anal verge). A technical description is provided; resections and postoperative complications in both groups are compared. Results: During the study period, 757 patients underwent TEM/TEO. Finally, 692 patients were included, 192 patients in group A and 500 patients in group B. An en bloc surgical specimen was obtained in 176/192 patients (91.7%), although the defect was completely sutured in 132 (68.8%). In the comparative analysis, group A did not present significantly greater fragmentation of the resected piece [16/192 (8.3%) vs. 36/500 (7.2%), p = 0.630], although group A was associated with greater involvement of the surgical margin [28/192 (14.6%), 32/500 (6.4%), p = 0.001] and clinically relevant morbidity [16/192 (8.3%), 20/500 (4%), p = 0.034]. There was no mortality. Conclusions: The use of TEM/TEO to remove lesions originating in the anal canal is feasible. But we have to take into account that there is an increase in complications, technical difficulties and affected margins resection.