Does transanal total mesorectal excision of rectal cancer improve histopathology metrics and/or complication rates? A meta-analysis.

BACKGROUND: The aim of this meta-analysis was to determine whether transanal total mesorectal excision (taTME) improves histopathology metrics and/or complication rates when compared to robotic total mesorectal excision (R-TME) of resectable rectal cancer.

METHODS: MEDLINE, Pubmed, Cochrane Library, and Scopus were systematically searched by two independent researchers. Six observational studies totaling 1,572 patients (811 taTME; 761 R-TME) were included after screening 14 potentially eligible records. Mantel-Haenszel method using odds ratios with 95% confidence intervals (OR (95%CI)) and inverse variance with mean difference with 95% confidence intervals (MD (95%CI)) as an effect measure for dichotomous and continuous variables, respectively, was employed for meta-analysis. Statistical heterogeneity among effect estimates was evaluated using I2 and Tau2 .

RESULTS: Circumferential resection margin (CRM) involvement rates (3.8% taTME; 5.3% R-TME) did not differ [OR (95%CI) = 0.86 (0.35, 2.15); p = 0.75] with low among-study heterogeneity (I2  = 21%). Complication rates (35.4% taTME; 32.3% R-TME) did not differ [OR (95%CI) = 0.92 (0.64, 1.32); p = 0.65], although with moderate among-study heterogeneity (I2  = 40%). CRM involvement [OR (95%CI) = 0.76 (0.40, 1.43); p = 0.40] and complication rates [OR (95%CI) = 0.84 (0.59, 1.21); p = 0.35] did not significantly differ in subgroup meta-analysis including mid- and low rectal cancer. Distal resection margin (mm) did not significantly differ between the interventions [MD (95%CI) = -0.41 (-1.29, 0.47); p = 0.37].

CONCLUSIONS: This meta-analysis found that taTME of rectal cancer does not improve histopathology metrics and complication rates when compared to R-TME.