Uni-center, patient-blinded, randomized, 12-month, parallel group, noninferiority study to compare outcomes of 3-row vs 2-row circular staplers for colorectal anastomosis formation after low anterior resection for rectal cancer

BACKGROUND: Colorectal anastomotic leakage (AL) is one of the most serious complications in rectal cancer surgery due to its negative impact on the overall as well as cancer-specific survival. Two-row stapling technique has become standard in low anterior resections (LARs), but has neither alleviated the morbidity, nor reduced the incidence of AL. This is the 1st study that aims to compare the success rate of new 3-row circular staplers compared to that of conventional 2-row staplers in a prospective, randomized clinical trial. METHODS: The THREESTAPLER trial (Clinical Trials NCT03910699) is a prospective, noninferiority, 2-armed, parallel-group, patient and outcomes assessor blinded study with a 1:1 allocation ratio. Colorectal anastomosis will be formed using Ethicon 29 mm Curved Intraluminal Stapler (CDH29A) in the active comparator group, and using Mirus Disposable Circular Stapler 3 Row 29 (MCS-29R3) in the experimental group. The hypothesis states that the incidence of AL in the 3-row stapler group is at least not higher than in the 2-row stapler group. Assuming there is a difference in success rate of 12% and noninferiority margin Δ = 5%, 154 patients will be required to achieve statistical significance. An interim analysis will be performed after recruitment of 20 patients per group to assess safety profile of 3-row circular staplers. The primary endpoint is the rate of AL, documented by imaging studies, assessed with Pearson Chi-squared test and Fisher exact test. The secondary outcomes include severity of AL (A, B, or C), anastomotic bleeding, postoperative complication rate graded with the Clavien–Dindo classification, reintervention rate, stapler dysfunction rate, complications of defunctioning stoma, overall and cancer-specific quality of life, assessed with short form (36) and quality-of-life questionnaire core 30 questionnaires, respectively, fecal incontinence assessed with Cleveland clinic incontinence score form, and manifestation of LAR syndrome. All patients will be monitored for 12 months following the LAR. DISCUSSION: This is the 1st prospective randomized trial to assess the safety profile of 3-row staplers for colorectal anastomosis after LAR for rectal cancer. It may provide evidence of feasibility of 3-row circular staplers in LAR with respect to short-term and long-term patient outcomes. Trial registration: NCT03910699 on 10 April 2019