PD-016 - Safety of self-expandable metal stents (SEMS) or emergency surgery for acute colonic obstruction in metastatic colon cancer patients treated with bevacizumab

Abstract

Introduction: Colorectal cancer presents with malignant bowel obstruction in about 10% of cases. SEMS can be an alternative for immediate surgery although long-term data is limited regarding clinical outcomes and safety of Bevacizumab (BV) in this subset of patients. The aim of this study was to evaluate procedure-related morbidity in relation to the type of previous or subsequent medical treatment used, including BV. Methods: We performed a retrospective review of 2850 cases of metastatic colon cancer diagnosed from January 2012 to October 2017, and identified those patients with malignant bowel obstruction that were initially treated with either SEMS or emergency surgery. Differences in procedure-related morbidity were assessed by the Chi-square test, overall survival (OS) with the log-rank test and a multivariate analysis with Cox proportional-hazards model was performed. Results: We selected 119 cases, 79 of which were treated with SEMS and 40 with surgery. Median age was 76. Median follow-up time was 11 months. No differences in sidedness or RAS status between cohorts. SEMS had a similar rate of complications compared to surgery (32.5% vs 35.5%, p = 0.45) and showed longer time to complications (18m vs 1m, p = 0.004). In patients treated with BV, complications were similar in SEMS and surgery groups (40% vs 31%, RR 1.28, p = 0.45), the incidence of perforation was similar in patients with SEMS compared to surgery (16% vs 7%, RR 1.09, p = 0.16) and when BV regimen is compared to chemotherapy alone (16% vs 6%, RR 1.11, p = 0.16). SEMS and surgery showed similar OS (14m vs 15m, p = 0.5). Treatment with BV increased OS in both the SEMS group (18 months vs 7 months, p = 0.001) and the surgery group (20 months vs 4 months, p = 0.001) compared to patients without subsequent medical treatment. Also, BV treatment showed a trend for longer OS when compared to chemotherapy alone in the SEMS group (18 months versus 15 months, p = 0.13) and in the surgery group (20 months versus 17 months, p = 0.13). In the multivariate analysis, patients treated with subsequent medical treatment showed a statistically significant longer OS [Hazard Ratio (HR) 0.43, Confidence Interval (CI) 95% 0.19-0.94, p = 0.02], patients with left-sided colon cancer showed a trend for longer OS (HR 0.5, CI95% 0.22-1.13, p = 0.09) and, in those patients who had complications, we observed shorter OS (HR 2.45, CI95% 1.17-5.12, p = 0.01). Conclusion: SEMS was associated with a similar outcome than emergency surgery and, furthermore, using BV was not associated with a higher risk of complication. In patients with metastatic colorectal cancer with acute malignant colon obstruction, SEMS is a safe option, including patients that received BV.