Single Versus Double Stapling and Two Purse-String Techniques in Rectal Cancer Surgery

This prospective, single-center randomized controlled trial will be conducted at the Colorectal Unit, Surgery Department, Faculty of Medicine, Alexandria University, Alexandria, Egypt. It will compare single-stapled and double-stapled anastomoses following low anterior resection with total mesorectal excision for rectal adenocarcinoma. Within the single-stapling group, a second randomized comparison will evaluate intracorporeal versus transanal placement of the rectal stump purse-string suture.

The study addresses whether avoiding the intersection between linear and circular staple lines influences anastomotic healing. It will also examine whether the route of purse-string placement affects surgical outcomes, pathological measures of oncological resection, and patient-reported bowel function and quality of life.

Randomization will take place intraoperatively after the surgeon confirms curative resectability and technical feasibility of the allocated approaches. Participants will first be randomized in a 1:1 ratio to single stapling or double stapling. Participants allocated to single stapling will then undergo a second 1:1 randomization to intracorporeal or transanal purse-string placement. The planned allocation is therefore 62 participants to double stapling, 31 to single stapling with an intracorporeal purse-string, and 31 to single stapling with a transanal purse-string.

An independent statistician will prepare the computer-generated randomization sequence. Allocation will be concealed using sequentially numbered, sealed, opaque envelopes until intraoperative randomization. Operating surgeons cannot be blinded. Outcome assessors, including imaging assessors, pathologists, and research staff administering patient-reported outcome questionnaires, will be blinded to allocation. Participants will remain blinded where feasible.

Experienced colorectal surgeons will perform standardized total mesorectal excision. In the double-stapling group, the rectum will be divided and closed with a linear stapler before creation of the anastomosis with a circular stapler. In the single-stapling groups, the rectum will be divided without a linear stapler, and the open rectal stump will be closed with an intracorporeal or transanal purse-string before circular stapling. A defunctioning stoma may be created at the operating surgeon's discretion according to clinical risk factors, and its use will be recorded.

Anastomotic leaks will be defined and graded using the International Study Group of Rectal Cancer classification. The primary comparison will assess clinically significant leaks requiring active treatment without relaparotomy or requiring relaparotomy, corresponding to Grade B or Grade C, within 30 days after surgery. Other postoperative complications will be classified using the Clavien-Dindo system.

Follow-up will assess postoperative recovery, anastomotic complications, pathological resection findings, and local recurrence through one year. Bowel function, fecal continence, and quality of life will be assessed using the Low Anterior Resection Syndrome score, Wexner incontinence score, and European Organisation for Research and Treatment of Cancer QLQ-C30 questionnaire at 6 and 12 months after surgery.

The sample size is based on the primary comparison between the combined single-stapling group and the double-stapling group. The primary analysis will follow the intention-to-treat principle, with a supplementary per-protocol analysis. Prespecified adjusted analyses will account for relevant clinical and operative factors. The intracorporeal versus transanal purse-string comparison will be analyzed separately within participants randomized to single stapling.

Participants will undergo low anterior resection with total mesorectal excision, followed by rectal transection and closure using a linear stapler. A transanally introduced circular stapler will then be used to create the colorectal or coloanal anastomosis. Planned enrollment is 62 participants.

Procedure: Double-Stapled Anastomosis

Participants will undergo low anterior resection with total mesorectal excision. The rectum will be transected without a linear stapler, and a manual purse-string suture will be placed intracorporeally to close the open rectal stump. A transanally introduced circular stapler will then be used to create the colorectal or coloanal anastomosis. Planned enrollment is 31 participants.

Procedure: Single-Stapled Anastomosis With Intracorporeal Purse-String

Participants will undergo low anterior resection with total mesorectal excision. The rectum will be transected abdominally without a linear stapler, and a purse-string suture will be placed through the anus to close the open rectal stump. A transanally introduced circular stapler will then be used to create the colorectal or coloanal anastomosis. Planned enrollment is 31 participants.

Procedure: Single-Stapled Anastomosis With Transanal Purse-String

Following low anterior resection with total mesorectal excision, a linear stapler will be used to transect and close the rectal stump. A circular stapler introduced through the anus will then be used to construct the colorectal or coloanal anastomosis.

Following low anterior resection with total mesorectal excision, the rectum will be transected using scissors or an energy device without linear stapling. A manual intracorporeal purse-string suture will be placed around the open rectal stump. A circular stapler introduced through the anus will then be used to construct the colorectal or coloanal anastomosis.

Following low anterior resection with total mesorectal excision, the rectum will be transected abdominally without linear stapling. A purse-string suture will be placed transanally around the open rectal stump. A circular stapler introduced through the anus will then be used to construct the colorectal or coloanal anastomosis.

Time frame: Within 30 days after surgery

Percentage of participants with an anastomotic leak classified as Grade B or Grade C according to the International Study Group of Rectal Cancer classification. Grade B requires active treatment without relaparotomy, and Grade C requires relaparotomy. The primary comparison will be between the combined single-stapling group and the double-stapling group.

Time frame: Within 30 and 90 days after surgery

Percentage of participants experiencing postoperative complications, with severity classified using the Clavien-Dindo system. Complications will be assessed cumulatively at 30 and 90 days after surgery, and the highest complication grade experienced by each participant will be recorded at each assessment.

Time frame: During the index operation

Duration of the surgical procedure, measured in minutes.

Time frame: During the index operation

Estimated volume of blood lost during the surgical procedure, measured in milliliters.

Time frame: During the index operation

Percentage of participants whose planned minimally invasive procedure is converted to open surgery. The denominator will include participants in whom a minimally invasive approach was initially attempted.

Time frame: From surgery to up to 10 weeks

Number of days from the index operation to discharge from the index hospital admission.

Time frame: At 6 and 12 months after surgery

Bowel function will be assessed using the five-item Low Anterior Resection Syndrome (LARS) score. Total scores range from 0 to 42, with higher scores indicating worse bowel dysfunction. Scores of 0-20 indicate no LARS, 21-29 indicate minor LARS, and 30-42 indicate major LARS. Scores will be evaluated separately at each assessment.

Time frame: At 6 and 12 months after surgery

Fecal incontinence will be assessed using the Wexner (Cleveland Clinic) Incontinence Score. The five-item score evaluates incontinence to solid stool, liquid stool, and gas, pad use, and lifestyle alteration. Total scores range from 0 to 20, with 0 indicating no incontinence and higher scores indicating more severe incontinence. Scores will be evaluated separately at each assessment.

Time frame: At 6 and 12 months after surgery

Health-related quality of life will be assessed using the European Organisation for Research and Treatment of Cancer QLQ-C30 questionnaire. Global health status/quality of life, functional scales, and symptom scales and items will be scored separately according to the scoring manual. Scores range from 0 to 100. Higher global health and functional scores indicate better quality of life or functioning; higher symptom scores indicate worse symptoms. Scores will be evaluated separately at each assessment.

Single Vs Double Stapling Technique & Intracorporeal Vs Transanal Purse-String in Low Anterior Resection for Rectal Cancer: An Adjusted Comparative RCT Evaluating Anastomotic Leak, Oncological and Patient-Reported Outcomes