Efficacy of uncovered colonic stents for extrinsic versus intrinsic malignant large bowel obstruction

Background: Previous studies evaluating self-expandable metal stents (SEMS) for management of malignant extrinsic colon obstruction have yielded conflicting results. We evaluated the efficacy of uncovered SEMS for extrinsic colon malignancy (ECM) versus intrinsic colon malignancy (ICM). Methods: Retrospective review of all patients referred for colonic SEMS at a tertiary cancer center between 2007 and 2018 was performed. Primary outcome measures were technical success, clinical success, intervention rate, and overall survival. Results: 138 patients with ECM and 119 patients with ICM underwent attempted stent placement. The rectum and/or sigmoid colon was the most common stricture site. Technical success was lower in the ECM group [86% vs 96% (p =.009)]. Clinical success was lower in the ECM group both at 7 days [82% vs 95% (p =.004)] and at 90 days [60% vs 86% (p <.001)]. Subsequent intervention was required more frequently [44% vs 35%; p =.23] and earlier [median 9 vs 132 days; p <.001] in the ECM group. Median overall survival in the ECM group was 92 vs 167 days. Among predictive variables analyzed, the ECM group had a higher frequency of peritoneal metastasis (87% vs 32%; p <.001), multifocal strictures with requirement for multiple stents (20% vs 6%; p =.002), sharp angulated strictures (39% vs 25%; p =.04) , and radiation therapy (21% vs 10%; p =.02). Conclusions: Colonic SEMS for ECM is associated with lower technical and clinical success with earlier intervention rates compared with ICM. Our findings can be used to better inform patients and referring providers as well as guide new stent design to enhance efficacy in this population.