Single-center comparative study of short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers

Background Transanal total mesorectal excision is a promising surgical treatment for rectal cancer. However, evidence regarding the differences in outcomes between the transanal and laparoscopic total mesorectal excisions is scarce. We compared the short-term outcomes of transanal and laparoscopic total mesorectal excisions for low and middle rectal cancers. Methods This retrospective study included patients who underwent low anterior or intersphincteric resection for middle (5–10 cm) or low (< 5 cm) rectal cancer at the National Cancer Center Hospital East, Japan, from May 2013 to March 2020. Primary rectal adenocarcinoma was confirmed histologically. Circumferential resection margins (CRMs) of resected specimens were measured; margins ≤ 1 mm were considered positive. The operative time, blood loss, hospitalization length, postoperative readmission rate, and short-term treatment results were compared. Results Four hundred twenty-nine patients were divided into two mesorectal excision groups: transanal ( n = 295) and laparoscopic ( n = 134). Operative times were significantly shorter in the transanal group than in the laparoscopic group ( p < 0.001). The pathological T stage and N status were not significantly different. The transanal group had significantly lower positive CRM rates ( p = 0.04), and significantly lower incidence of the Clavien–Dindo grade III ( p = 0.02) and IV ( p = 0.03) complications. Both groups had distal margin positivity rates of 0%. Conclusions Compared to laparoscopic, transanal total mesorectal excision for low and middle rectal cancers has lower incident postoperative complication and CRM-positivity rates, demonstrating the safety and usefulness of local curability for middle and low rectal cancers.