Tu1026 Mortality and Recurrence After Colorectal Cancer Resection With Preoperative Stenting -A Danish Nationwide Cohort Study

Background: Self-expanding metal stents (SEMS) used as a bridge to surgery for obstructive colorectal cancer (CRC) have fallen under suspicion for inducing tumor dissemination and thereby increasing CRC recurrence and long-term mortality, but data regarding these risks are sparse. Several attempts to compare SEMS with acute surgery in randomized settings have failed and the existing evidence from observational studies is based primarily on singlecenter studies conducted in highly specialized settings with little or no information on potential confounding factors.Methods:We conducted a nationwide population-based cohort study using Danish medical registries (2005-2010) by comparing overall mortality and recurrence after CRC resection in patients with preoperative stenting (n=581) to patients undergoing urgent (n=3,333) or elective resection (n=13,722). For patients surviving the first 30 days after CRC resection, we used the Kaplan Meier method to compute absolute survival. For CRC patients with localized and regional disease, the risk of CRC recurrence was estimated treating death as a competing risk. We computed mortality rate ratios (MRRs) and cause specific hazard ratios of recurrence within 5 years, using Cox regression with adjustment for important covariates. Results: Crude 5-year survival was 49% (95% CI: 43%55%) among patients with preoperative SEMS, 40% (95% CI: 38%-43%) among patients undergoing urgent resection, and 65% (95% CI: 64%-66%) among patients with elective resection. For SEMS vs. urgent resection, the adjusted MRR was 0.99 (95% CI: 0.91-1.07) and for SEMS vs. elective resection, the adjusted MRR was 1.39 (95% CI: 1.19-1.62). The 5-year recurrence risk was 39% (95% CI: 31%-46%) after preoperative SEMS, 30% (95% CI: 27%-32%) after urgent resection, and 22% (95% CI: 21%-24%) after elective surgery. The adjusted cause-specific hazard ratios for recurrence were 1.13 (95% CI: 0.99-1.28) for SEMS vs. urgent resection and 1.81 (95% CI: 1.44-2.28) for SEMS vs. elective resection. Conclusions: Long-term mortality associated with use of SEMS as a bridge to surgery was comparable to that of urgent resection, but higher than that observed following elective resection. SEMS use may be associated with an increased risk of CRC recurrence.