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Introduction
In the past years the incidence of colorectal cancer (CRC) increased to 14.1 million new cases worldwide in 2012 [1]. Patients diagnosed with CRC present in 8% with colorectal obstruction causing nausea, vomiting, constipation, and abdominal distension [2].
Obstructing CRC is a potentially life-threatening condition that can lead to colonic necrosis and blow-out perforations. Emergency resection or endoscopic self-expanding metal stent (SEMS) placement are the treatment options in the acute setting. Resection often requires laparotomy with stoma formation and has a high morbidity (54%) and mortality (12%) [3]. In the elderly and frail patients who have a high surgical risk as well as for patients with incurable metastatic disease, SEMS placement can be considered as initial treatment for colonic decompression [4, 5]. A randomized trial that compared SEMS placement with primary surgery for the palliation of colorectal obstruction was closed early because 6 out of 10 patients treated with SEMS placement developed a perforation. The authors speculated that the administration of systemic chemotherapy could have contributed to the risk of stent perforation [6]. Although based on low-quality evidence, the literature data suggest that in particular systemic treatment with bevacizumab, a monoclonal antibody that binds to vascular endothelial growth factor (VEGF) and thereby inhibits angiogenesis, increased the risk of stent perforations. A meta-analysis of pooled literature data found that patients treated with bevacizumab-based systemic therapy had a 12.5% risk of stent perforation [7].
First-line systemic therapy in metastatic CRC includes fluoropyrimidine-containing chemotherapy plus bevacizumab [8]. The AVEX trial [9] randomized elderly patients with metastatic CRC to receive first-line treatment with capecitabine with or without bevacizumab. Addition of bevacizumab to capecitabine significantly increased response rates and progression-free survival (9.1 vs. 5.1 months, p < 0.0001). A meta-analysis of nine trials investigated the efficacy and safety of bevacizumab plus chemotherapy compared to chemotherapy alone in previously untreated, advanced, or metastatic CRC. Patients who received both chemotherapy and bevacizumab had higher response rates (RR = 0.89; 95% CI = 0.82–0.96; p = 0.003) with heterogeneity, higher progression-free survival (HR = 0.69; 95% CI = 0.63–0.75; p < 0.00001), and also higher overall survival rates (HR = 0.87; 95% CI = 0.80–0.95; p = 0.002) with moderate heterogeneity [10], so the addition of bevacizumab to palliative chemotherapy regimens...