A systematic review of stenting for bowel obstruction for extracolonic malignancies - a data deficit?

Abstract

BACKGROUND Self expandable metallic stents (SEMS) for obstructing colon cancer (CRC) is well established. Limited data suggest stenting for large bowel obstruction (LBO) due to extra-colonic malignancy (ECM) has a worse outcome than primary CRC. AIM To perform a systematic review with subgroup analysis of randomised controlled trials (RCTs) comparing stenting and surgery for outcomes in ECM vs. CRC. METHOD1 A detailed electronic search was carried out from the following databases: Cochrane Central Register of Controlled Trials, MEDLINE, Embase and PubMed. The search was performed using the terms ‘colonic obstruction’, ‘intestinal obstruction’, or ‘large bowel obstruction’, ‘stent’ or ‘colorectal stent’, or ‘bridge’. No language limitation was applied to the search. All studies published from 1990 to 2018 were considered. Abstracts of potentially relevant publications based on the titles were read and comparative studies of SEMS vs. emergency surgery retrieved. A hand-search of the references of all comparative studies retrieved was undertaken for any further potential studies; these were then reviewed. Patient subgroups were examined to extract ECM cases to evaluate outcome. RCTs deemed relevant were then screened using the assessment tool as shown in Fig 1. Studies that scored 2 or less were excluded from the review RESULTS None of the studies retrieved for this systematic review included data of sufficient quality enabling measurement of outcome in LBO due to ECM vs. CRC. DISCUSSION Limited lower quality evidence in the form of cohort studies or retrospective reviews suggest outcome of SEMS in ECM has a worse outcome than CRC. Possible reasons include bulkier tumours, increased fibrosis secondary to radiotherapy, or the presence of peritoneal carcinomatosis. Whilst the RCTs assessed in this review report the complication rates for SEMS vs. surgery for CRC, it is worth noting that the complication rate of endoscopic stenting for ECM may be similar to the surgical complication rate. CONCLUSION Currently no available Level 1 data exists to allow for subgroup analysis comparing the efficacy or safety of SEMS in ECM. An RCT comparing SEMS vs. surgery for LBO due to ECM is needed to clarify the efficacy and safety of stenting in patients with ECM.