Oncological outcomes for transanal total mesorectal excision

Abstract

: Total mesorectal excision (TME) has become the gold standard technique for rectal cancer surgery with curative intent. Advantages in technology and surgical innovation lead to the introduction of minimally invasive techniques including laparoscopic, robotic and, more recently, transanal TME (TaTME). The concept of TaTME has been proposed to overcome the technical challenges encountered with the transabdominal approaches (open, laparoscopic, robotic) in the most difficult cases (obese, male patients with mid-low rectal cancer and a narrow, radiated pelvis and bulky mesorectum). Additionally, it has been recently claimed that TaTME offers at least 3 oncological advantages: (I) a longer distal resection margin (DRM), (II) a decreased rate of positive circumferential resection margin (CRM), (III) improved quality of TME. However, the oncological outcomes of TaTME compared to those of laparoscopic and robotic TMEs, remain controversial. Hence, a review of all the literature examining oncological outcomes after TaTME was performed. Two reviewers independently conducted a search of electronic databases (PubMed, MEDLINE, Cochrane Library). The last search was performed on August, 30th 2019. After the initial screen of 326 articles, 32 papers were selected for review, of these 19 were comparative studies and 1 a randomized controlled trial. TaTME resulted to provide oncologic outcomes at least comparable with the other minimally invasive approaches (laparoscopic, robotic) and seems to be associated with a lower rate of CRM involvement and TME incompleteness when compared to the laparoscopic, robotic, open approaches. Scarcity of data and short follow-up time made it impossible to draw conclusions on long-term oncologic outcomes. Hopefully, the COLOR III multicenter RCTs will shed a light on short- and long-term oncologic outcomes after TaTME.