Is Endoscopic Submucosal Dissection Truly Comparable to Transanal Endoscopic Microsurgery for Early Rectal Epithelial and Subepithelial Tumors? A Meta-Analysis

<b><i>Background:</i></b> Early rectal tumors can be effectively managed using transanal endoscopic microsurgery (TEM) and endoscopic submucosal dissection (ESD). This study aimed to compare ESD and TEM in the resection of early rectal tumors concerning <i>en bloc</i> resection rates, R0 resection rates, mean procedural times, perforation rates, bleeding rates, adverse events/complication rates, and mean length of stay (LOS). <b><i>Methods:</i></b> We conducted a systematic literature review in accordance with PRISMA guidelines to identify studies directly comparing ESD and TEM for the resection of early rectal tumors. A pairwise meta-analysis was performed using a random-effects model, reporting odds ratios and mean differences. <b><i>Results:</i></b> The R0 resection rate was lower in the ESD group. Subgroup analysis indicated that the reduced R0 resection rate in ESD remained significant in the subepithelial subgroup but not in the epithelial subgroup, with the subgroup difference reaching statistical significance (<i>P</i> = .05) but didn't meet conventional statistical significance (<i>P</i> < .05). The number needed to treat with ESD to result in one additional missed R0 resection (harmful event) compared to TEM was 10 (95% CI 4-162). The ESD group demonstrated significantly shorter mean procedural times and LOS, with no significant subgroup differences between epithelial and subepithelial tumors. <b><i>Conclusions:</i></b> This study suggests that ESD is associated with a lower R0 resection rate compared to TEM, but offers a shorter mean LOS and procedural time. To date, no randomized controlled trials (RCTs) have been published. Large-scale RCTs that also involve operators who have achieved technical mastery in ESD and TEM are necessary to reach more definitive conclusions. Until such RCTs are published, strong recommendations cannot be made. Additionally, further studies are required to assess whether tumor origin (epithelial versus subepithelial) impacts the R0 resection rate in ESD.