Rectal Surgery Evaluation Trial: protocol for a parallel cohort trial of outcomes using surgical techniques for total mesorectal excision with low anterior resection in high-risk rectal cancer patients.

AIM: Total mesorectal excision (TME) is the standard of care for rectal cancer, which can be combined with low anterior resection (LAR) in patients with mid-to-low rectal cancer. The narrow pelvic space and difficulties in obtaining adequate exposure make surgery technically challenging. Four techniques are used to perform the surgery: open laparotomy, laparoscopy, robot-assisted surgery and transanal surgery. Comparative data for these techniques are required to provide clinical data on the surgical management of rectal cancers.

METHODS: The Rectal Surgery Evaluation Trial will be a prospective, observational, case-matched, four-cohort, multicentre trial designed to study TME with LAR using open laparotomy, laparoscopy, robot-assisted surgery or transanal surgery in high-surgical-risk patients with mid-to-low non-metastatic rectal cancer. All surgeries will be performed by surgeons experienced in at least one of the techniques. Oncological, morbidity and functional outcomes will be assessed in a composite primary outcome, with success defined as circumferential resection margin ≥ 1 mm, TME Grade III and minimal postoperative morbidity (absence of Clavien-Dindo Grade III-IV complications within 30 days after surgery). Secondary end-points will include the co-primary end-points over the long term (2 years), quality of surgery, quality of life, length of hospital stay, operative time and rate of unplanned conversions.

DISCUSSION: This will be the first trial to study all four surgical techniques currently used for TME with LAR in a specific group of high-risk patients. The knowledge obtained will contribute towards helping physicians determine the advantages of each technique and which may be the most appropriate for their patients.