Bridging to Surgery Versus Palliation in Malignant Colorectal Obstruction: Complication Risks and Mediation by Clinical Success

Background Self-expandable metal stents (SEMS) are routinely used in malignant colorectal obstruction (MCO) for palliation or as a bridge to surgery. However, whether treatment intent influences complication risk, and if clinical success mediates this relationship, remains unclear. Methods We retrospectively analyzed 413 patients with MCO who underwent SEMS placement between 2014 and 2024. Patients were categorized by therapeutic intent (palliation vs. bridge to surgery), and complication rates were compared. Mediation analysis was performed using the Sobel test, structural equation modeling (SEM), and bootstrap-based causal mediation to assess whether clinical success mediated the relationship between therapeutic purpose and complications. Results Complications occurred in 60 patients (14.5%). Palliation was associated with a higher complication rate compared to bridging (20.0% vs. 8.0%, p = 0.001). Clinical success significantly mediated the effect of therapeutic purpose on complications (Sobel p = 0.035). SEM confirmed a positive association between therapeutic purpose and clinical success (standardized β = 0.171, p < 0.001) and a negative association between clinical success and complications (β = –0.191, p = 0.009). Bootstrap mediation analysis revealed that 13.0% of the total effect was mediated through clinical success (p = 0.031). Conclusions Therapeutic intent affects SEMS complication risk, mediated by clinical success. Optimizing outcomes—especially in palliation—enhances safety and guides personalized management