Role of a Preoperative Completion Colonoscopy in Patients With Obstructed Colorectal Cancer Post Self‐Expandable Metallic Stent ( <scp>SEMS</scp> ) Placement as a Bridge to Surgery ( <scp>BTS</scp> )

ABSTRACT Background In patients with obstructed colorectal cancer (CRC), a self‐expandable metallic stent (SEMS) can be placed across the tumor as a bridge‐to‐surgery (BTS). Following stent decompression of the obstructed bowel, it becomes feasible to assess the proximal colon for synchronous neoplastic lesions. The aim of this study is to examine the role of a preoperative completion colonoscopy in the management of stented patients prior to definitive surgery and to determine whether this affects operative management. Methods From 2004 to 2023, all patients admitted under the Department of Colorectal Surgery in our institution who underwent SEMS for obstructed CRC were retrospectively reviewed from a prospectively collected database. The number of patients who had a preoperative completion colonoscopy was analyzed for the presence of synchronous colonic tumors, benign adenomas, and mucosal ischemia. Results A total of 140 patients with obstructed CRC underwent SEMS. SEMS was successful in 126 patients. One hundred and two patients had SEMS as a BTS, and a preoperative colonoscopy was attempted in 30 of these patients. Full colonoscopy through the stent was successful in 24 patients without complications. Six preoperative colonoscopies failed due to inadequate stool clearance in the proximal colon or technical difficulties in traversing the colonoscope through the stent or colon. A synchronous tumor was detected in 1 of the 24 successful procedures, located distal to the obstructed sigmoid tumor. Additionally, mucosal ischemia was noted in the proximal colon in 4 of the 24 patients, which required adjustment of the resection margins. One patient underwent a subtotal colectomy instead of a segmental colectomy due to multiple adenomas proximal to the stented tumor. Of the stented patients who did not undergo preoperative colonoscopy, one patient required a defunctioning stoma due to ulceration proximal to the stented tumor seen at the time of surgery, while another was later found to have an obstructing metachronous cancer requiring repeat emergency surgery. Twenty‐eight out of 78 stented patients (35.9%) who did not have preoperative colonoscopy never underwent completion colonoscopy even after surgery. Conclusion Preoperative completion colonoscopy after SEMS placement in patients with obstructed CRC is safe, aids in surgical planning, and prevents missed lesions.