Key Message
There is strong evidence based on five high-to-moderate quality systematic reviews and six moderate-to-low quality non-randomized studies that suggests that Transanal Total Mesorectal Excision is clinically effective and safe for patients with rectal cancer based on the assessment of short-term outcomes when compared to Laparoscopic Total Mesorectal Excision. Limited evidence from two non-randomized trials was insufficient to be make statements regarding the clinical effectiveness of Transanal Total Mesorectal Excision compared with Open Total Mesorectal Excision based on the assessment of short-term outcomes.Insufficient evidence regarding long-term clinical effectiveness was identified for Transanal Total Mesorectal Excision for adult patients with rectal cancer compared to Open or Laparoscopic Total Mesorectal Excision. Conclusions based on comparative long-term clinical effectiveness cannot be made.No evidence regarding the cost-effectiveness of Transanal Total Mesorectal Excision for adult patients with rectal cancer was identified in comparison to open or Laparoscopic Total Mesorectal Excision.