Transanal endoscopic microsurgery versus radical resection for early-stage rectal cancer: a systematic review and meta- analysis

In the treatment of early-stage rectal cancer, a growing number of studies have shown that transanal endoscopic microsurgery is one of the alternatives to radical surgery adhering to total mesorectal excision that can reduce the incidence of adverse events without compromising treatment outcomes. The purpose of this meta-analysis is to compare the safety and treatment effect of transanal endoscopic microsurgery and radical surgery adhering to total mesorectal excision to provide a basis for clinical treatment selections.We searched the literatures of four major databases, PubMed, Embase, Web of science, and Cochrane Library, without limitation of time. The literatures included randomized controlled studies and cohort studies comparing two surgical procedures of transanal endoscopic microsurgery and radical surgery adhering to total mesorectal excision. Treatment effectiveness and safety results of transanal endoscopic microsurgery and radical surgery were extracted from the included literatures and statistically analyzed using RevMan5.4 and stata17.Ultimately, 13 papers were included in the study including 5 randomized controlled studies and 8 cohort studies. The results of the meta-analysis showed that the treatment effect and safety of both transanal endoscopic microsurgery and radical surgery in distant metastasis (RR, 0.59 (0.34, 1.02), P > 0.05), overall recurrence (RR, 1.49 (0.96, 2.31), P > 0.05), disease-specific-survival (RR, 0.74 (0.09, 1.57), P > 0.05), dehiscence of the sutureline or anastomosis leakage (RR, 0.57 (0.30, 1.06), P > 0.05), postoperative bleeding (RR, 0.47 (0.22, 0.99), P > 0.05), and pneumonia (RR, 0.37, (0.10, 1.40), P > 0.05) were not significantly different. However, they differ significantly in perioperative mortality (RR, 0.26 (0.07, 0.93, P < 0.05)), local recurrence (RR, 2.51 (1.53, 4.21), P < 0.05),_overall survival_ (RR, 0.88 (0.74, 1.00), P < 0.05), disease-free-survival (RR, 1.08 (0.97, 1.19), P < 0.05), temporary stoma (RR, 0.05 (0.01, 0.20), P < 0.05), permanent stoma (RR, 0.16 (0.08, 0.33), P < 0.05), postoperative complications (RR, 0.35 (0.21, 0.59), P < 0.05), rectal pain (RR, 1.47 (1.11, 1.95), P < 0.05), operation time (RR, -97.14 (-115.81, -78.47), P < 0.05), blood loss (RR, -315.52 (-472.47, -158.57), P < 0.05), and time of hospitalization (RR, -8.82 (-10.38, -7.26), P < 0.05).Transanal endoscopic microsurgery seems to be one of the alternatives to radical surgery for early-stage rectal cancer, but more high-quality clinical studies are needed to provide a reliable basis.