Abstract: We found only one RCT meeting the selection criteria for the second objective (therapeutic potential) of this review. This study recruited nine participants. It compared the use of gastrografin versus placebo in adult patients with MBO with no indication for further intervention (surgery, endoscopy) apart from standardised conservative management. The overall risk of bias for the study was high due to issues with low numbers of participants, selective reporting of outcomes and a high attrition rate for the intervention arm. Primary outcomes The included trial was a pilot study whose primary outcome was to test the feasibility for a large study. The authors reported specifically on the number of patients screened, the number recruited and reasons for exclusion; this was not the focus of our review. Due to the low number of participants, the authors of the study decided not to report on our primary outcome of assessing the ability of OWSC to predict the likelihood of malignant small bowel obstruction resolving with conservative treatment alone (diagnostic effect). It also did not report on our primary outcome of rate of resolution of MBO in patients receiving OWSC compared with those not receiving it (therapeutic effect). The study reported that no issues regarding safety or tolerability of either gastrografin or placebo were identified. The overall quality of the evidence for the incidence of adverse events with OWSC was very low, downgraded twice for serious limitations to study quality (high risk of selective reporting and attrition bias) and downgraded once for imprecision (sparse data). Secondary outcomes The study planned to report on this review’s secondary outcome measures of length of hospital stay and time from administration of OWSC to resolution of MBO. However the authors of the study decided not to do so due to the low numbers of patients recruited. The study did not report on our secondary outcome measure of survival times from onset of inoperable MBO until death. There is insufficient evidence from RCTs to determine the place of OWSC in predicting which patients with inoperable MBO will respond with conservative treatment alone. There is also insufficient evidence from RCTs to determine the therapeutic effects and safety of OWSC in patients with malignant small bowel obstruction.

Plain-language summary: We searched for evidence that OWSC could be used to identify which patients with inoperable MBO would recover with conservative management. We also wanted to know if OWSC increased the likelihood of recovery from MBO, reduced hospital stay or improved prognosis. Finally, we wished to know what side effects OWSC might cause for patients with MBO. We conducted the search in June 2017 and found one study. It only recruited nine participants and did not fully report on the outcomes of using OWSC in MBO. We found insufficient evidence that OWSC can identify which patients with MBO will recover with conservative management. We found insufficient evidence that patients with MBO benefit from OWSC in terms of length of hospital stay, recovery time or survival. No conclusions could be made about side effects from OWSC. We rated the quality of the evidence from studies using four levels: very low, low, moderate, or high. Very low-quality evidence means that we are very uncertain about the results. High-quality evidence means that we are very confident in the results. We rated the quality of the evidence as very low due to the lack of studies reporting on the benefits of using OWSC in MBO and the only study we found reporting on side effects recruited very few participants (nine). The low quality of the evidence means that we are very uncertain about the use of OWSC in the management of MBO and cannot confirm its benefits or harms in patients with this condition.