Transanal total mesorectal excision for rectal cancer: a single center experience and systematic review of the literature

Purpose The present study aimed to compare the operative and oncologic results of transanal total mesorectum excision (Ta-TME) ("down-to-up") vs. laparoscopic TME (L-TME, "up-to-down") for low rectal cancer. Additionally, a systematic review of the literature was performed to assess the quality of the current body of evidence on Ta-TME. Methods The study population included 32 consecutive patients who underwent Ta-TME between January 2011 and December 2014 that were compared with a matched group of patients undergoing L-TME between January 2008 and December 2010. The literature search was performed following the PRISMA guidelines for a systematic review. Results Ta-TME was associated with significantly shorter operative time (195 vs. 225 min; p=0.017) and hospital stay (7.8 vs. 9.7 days; p=0.018) compared to L-TME. No group differences were observed for intra-/postoperative complications and oncologic outcomes. One patient in the Ta-TME and two patients in the L-TME group developed local recurrence. The estimated survival rate at 2 years was 95.5 % for the Ta-TME and 96.6 % for the L-TME group (p=0.646). The literature search identified 22 relevant retrospective studies on 423 patients operated on Ta-TME or robotic-assisted transanal TME for rectal cancer. The only two comparative studies found similar short-term oncologic outcomes between Ta-TME and L-TME. A complete mesorectum was observed in 85 % of Ta-TME cases. The conversion rate was estimated at 4.3 % and the postoperative complication rate at 30.4 %. Conclusions Ta-TME appears to be safe and feasible. It may find special application in patients with anatomic constraints that could make L-TME highly challenging.