Background: Anastomotic leakage (AL) after colorectal surgery remains a significant challenge, associated with increased morbidity, mortality, poor oncological outcomes, and reduced quality of life. Despite surgical advances, AL rates for colorectal procedures continue to range from 3% to 25%, especially in distal anastomoses.

The commonly used cross-stapled circular anastomosis for anterior resections (AR) activates a foreign body response delaying gastrointestinal wound healing and potentially increasing the risk of AL. Additionally, crossed stapler lines further increase the risk of AL. An adaptive anastomosis technique eliminates permanent foreign body material, thereby reducing negative effects on wound healing and avoiding cross-stapling potentially lowering the incidence of AL. These areas have shown to have a lower burst pressure compared to a single stapled anastomosis.

An adaptive anastomotic technique eliminates cross-stapling and permanent foreign body material in the anastomosis reducing the negative effects on wound healing potentially lowering the incidence of AL.

Design: This is a prospective, international, non-randomized, multicentre study.

Endpoints: The Primary objective of this trial is to assess the incidence of AL within 30 days after surgery. Secondary objectives are to assess anastomotic integrity at 90 days and 1 year, intraoperative efficacy and efficiency of the C-REX device, time to evacuation of the anastomotic ring, mode of evacuation and related patient experience, postoperative morbidity and readmissions, C-reactive protein (CRP) profile in the early postoperative period, functional outcomes, cost-effectiveness and surgical quality.

Population: A total of 165 patients (age ≥ 18 years) with histologically proven cT1-4aN0-2M0 cancer of the sigmoid colon or proximal rectum, or premalignant lesions not amenable to endoscopic resection, that require elective AR will be enrolled throughout 10 European colorectal centers.

Study procedures: The anastomosis will be created using the C-REX RectoAid Cath. The healing period will be approximately 10 days. The anastomotic ring detaches via necrosis and is evacuated with the feces. Patients will be asked to fill out questionnaires regarding Low Anterior Resection Syndrome (LARS) and use of healthcare and these will be gathered preoperatively, 90 days postoperative and 1 year after surgery. At 12 months a CT-scan and colonoscopy will be performed.

Detailed description of device and surgical procedure:

During the surgical procedure, the colorectal anastomosis will be created using the C-REX RectoAid Cath (Carpo Novum AB, Halmstad, Sweden). The C-REX devices are CE-marked and used in its intended purpose in this trial. The C-REX RectoAid Cath is a refined anastomotic device that facilitates the construction of an inverted serosa-to-serosa adaptive colorectal anastomosis where the bowel ends are held together by snap-locking a proximal and distal silicone anastomotic ring. The C-REX devices can be used in both open and minimally invasive procedures. The proximal limit for C-REX RectoAid Cath is 25 cm above the anal verge and the distal limit is formed by the anal ring.

The anterior resection using the C-REX RectoAid Cath is performed by experienced colorectal surgeons who received training to use the C-REX device from an experienced Clinical Field Trainer from Carpo Novum AB. After bowel resection and measuring of the lumen using the C-REX Test Device, the proximal ring is placed using the C-REX LapAid. This device ensures that the colonic wall is folded around the anastomotic ring. Once this colonic ring is in position, the anvil is connected whereby catheters are placed into the colonic lumen. Subsequently, the C-REX RectoAid can be inserted transanal. In similarity to ordinary stapler devices, a concealed trocar becomes visible by rotating the knob on the base of the handle of the C-REX RectoAid. When possible, the stapler line of the transected proximal rectal stump is invaginated into the distal anastomotic C-REX ring and thus removed at firing of the RectoAid instrument. The trocar and proximal anvil are connected and by turning the knob clockwise, the gap between the anvil and the head of the instrument is closed. After firing the device, the two anastomotic rings are connected and the anastomosis is created. The four integrated catheters will be extracted simultaneous with the RectoAid instrument and can be used to measure the Anastomotic contact pressure (ACP) to validate the anastomosis. These catheters are in direct contact with the anastomotic healing site. When the anastomotic rings detach during the healing process by necrosis, after approximately 10 days, the anastomotic ring loosens from of the intestinal wall and is expelled with the feces.

Inclusion Criteria:

• Biopsy proven cancer of the sigmoid colon or proximal rectum (cT1-4aN0-2M0) that require AR as the procedure of choice or premalignant lesions not amenable to endoscopic resection, that require AR as the procedure of choice.
• Suitable for curative AR
• Suitable for elective laparoscopic or robotic surgery
• Cognitive ability to take part in the study, to understand the information the patient receives about participating in the study, to provide informed consent and to agree to complete the questionnaires.

Exclusion Criteria:

• Pre-existing health conditions requiring emergency surgery, such as intestinal obstruction or perforation, local or systemic infections, peritonitis, or intestinal ischemia.
• Cancer with distant metastases (TNM Stage IV).
• Intestinal or anal stenosis or other obstructions distal to the planned anastomosis.
• Prior pelvic radiation including neoadjuvant chemoradiotherapy.
• Contraindications to general anaesthesia.
• Need for defunctioning ileostomy (intention to treat).
• Patients who have a contra-indication for or are unable to receive preoperative bowel preparation or at least two enemas prior to surgery.
• Immunocompromised patients e.g. taking steroids or receiving immunotherapy.
• Any condition that, in the opinion of the investigator, may interfere with the study conduction. In particular, any condition which can cause significant alteration of colonic wall thickness such as chronic and repeated infection (e.g. diverticulitis) which may impair the use of C-REX RectoAid Cath

165 Patients (age ≥ 18 years) with histologically proven cT1-4aN0-2M0 cancer of the sigmoid colon or proximal rectum, or with premalignant lesions not amenable to endoscopic resection, that require AR as the procedure of choice