Self-expandable Metal Stent (SEMS) Endoscopic Placement for Malignant Colonic Obstruction Therapy (PATENCY)

Randomized Non-inferiority Single-center Prospective Trial of Malignant Colonic Obstruction Therapy With Self-expandable Metal Stent (SEMS) Endoscopic Placement or Stoma Formation.

Compare the effectiveness of Self-expandable metal stent (SEMS) and diverting stoma formation for the bowel preparation as a bridge to surgical treatment of patients with MCO.

Surgical treatment of MCO is associated with high mortality and frequent development of postoperative complications. Stoma formation is the traditional method of urgent treatment of MCO. Currently there are more than 150 methods of colorectal stomas formation, but all of themare associated with a high risk of complications (10-20%), inclusively both early and late postoperative period. It results in longerhospital stay and requires additional financial expenses, also reoperations can be fatal for patients. Analysis of recent publications devoted to the treatment of MCO shows increasing implemented of new strategies of patents management, such as "fast track surgery", or "fast track recovery strategy" in clinical practice. Minimally invasive endoscopic procedures as a first stage of MCO treatment leads to transformation of previously performed multi-stage surgical interventions into one - stage. Development of up-to-date endoscopic science and technology provides a wide usage ofself-expandable metal stent (SEMS) in clinical practice. This strategy helps to avoid stoma formation or emergency surgery, becoming a "bridge" to a radical surgery. There are currently no studies directly comparing discharge stoma with endoscopic self-expandable metal stenting in preparation for colorectal cancer radical surgery.

Anesthesia will include only propofol injection. A covered or partially covered metal self- expanding stent is placed in the area of tumor stenosis by the conductor, symmetrically in relation to the area of tumor stenosis.

Anesthetic care will include general endotracheal anesthesia with positioning of nasogastric tube and bladder catheterization. The diverting stoma formation will be proceed in 10 sm proximally to tumor.

Trocar placement: the optical trocar (10 mm) will be inserted just near umbilicus . An abdominal revision is performed to determine the location of the tumor. Colon in 10 sm proximally to tumor is prepared for the discharge stoma formation. In the corresponding location on the anterior abdominal wall is formed incision of skin and subcutaneous tissue to the aponeurosis, the cut length is 2.5 sm. After that, aponeurosis crucial incision is performed. The previously prepared colon is brought out to the anterior abdominal wall with the help of a grasper. Discharge stoma is attached to a holding device; colon is fixed by the interrupted sutures (Polysorb 3-0). In the operating room, the stoma is opened, the intestinal patency is checked in both directions, and hemostasis is revealed. With the help of optics, the presence of intestinal tension is checked; if necessary, the colon is additionally mobilized.

The colonoscope is passed to the distal edge of the tumor and a biopsy of the tumor is performed (if the tumor has not previously been verified). Through the tumor stenosis radioscopically guided metal conductor with atraumatic distal end installs in the proximal colon. A covered or partially covered metal self- expanding stent is placed in the area of tumor stenosis by the conductor, symmetrically in relation to the area of tumor stenosis. Radioscopically and endoscopically guided disclosure of a SEMS is performed immediately after which there is an abundant discharge of gases and intestinal contents. Upon completion of the procedure, the patient is transferred to the patient's room. The next day, a control X-ray of the abdomen is taken.

Evaluated via colonoscopy in colon and rectum distal to the tumour. Total score of bowel preparation measured from 0 to 9. The maximum BBPS score for a perfectly clean colon without any residual liquid is 9 and the minimum BBPS score for an unprepared colon is 0. This is evaluated by the endoscopist

The percentage of patients who had preventive or definitive stoma during resectional surgery in the SEMS group

Inclusion Criteria: Patients are 18 years old or older Stage I-IV according to TNM classification Patients with malignant colonic obstruction Overall health status according to ASA classification: I-III Overall health status according to Charlson comorbidity index ≤ 8 points Signed informed consent with agreement to attend all study visits The patient is not pregnant Exclusion Criteria: Inflammatory bowel disease Acute purulent process in the abdominal cavity The patient wants to withdraw from the clinical trial Loss to follow-up

Clinic of colorectal and minimally invasive surgery University Hospital n2, Clinical Center Sechenov First Moscow State Medical University

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