WSES–PSOGI–SICO evidence-infomed guidelines on surgical emergencies in patients with peritoneal surface malignancies: a systematic review, meta-analysis, and structured expert consensus

Peritoneal surface malignancies (PSM) are primary or secondary neoplastic deposits involving the peritoneum and are commonly associated with colorectal, gastric, appendiceal, gynecological, pancreaticobiliary, and other intra-abdominal or extra-abdominal cancers. Malignant bowel obstruction (MBO) is one of the most frequent and clinically consequential emergency presentations in this population, yet diagnostic and therapeutic pathways remain heterogeneous. We aimed to develop evidence-informed recommendations for emergency management of MBO in patients with PSM by integrating a systematic review, meta-analysis and a structured international expert consensus process. This systematic review, meta-analysis, and Delphi consensus followed PRISMA, Cochrane, and relevant MOOSE reporting principles. PubMed/MEDLINE and the Cochrane Library were searched from inception to June 2025 (English language). Five predefined PICO/PIRT questions addressed: (1) the diagnostic role of CT, plain abdominal X-ray, or Gastrografin-enhanced X-ray in PSM-related MBO; (2) nonoperative medical management versus surgical or endoscopic therapy; (3) surgical versus endoscopic treatment after failure of nonoperative management; (4) bowel resection versus stoma or bypass in surgical candidates; and (5) endoscopic stenting versus endoscopic ultrasound-guided bypass with lumen-apposing metal stents in endoscopic candidates. Study selection and data extraction were performed independently and in duplicate. Risk of bias was assessed with ROBINS-I for comparative non-randomized studies and MINORS for non-comparative studies; certainty of evidence was rated with GRADE. Random-effects meta-analyses (REML) produced odds ratios (OR), mean differences (MD), pooled means, or pooled proportions with 95% confidence intervals (CI); heterogeneity was summarized using I2, τ2, and 95% prediction intervals. Evidence profiles informed statements voted on by the WSES-PSOGI-SICO expert panel during the 2025 WSES Congress. No comparative diagnostic study evaluated abdominal X-ray or Gastrografin-enhanced X-ray in PSM-related MBO; two small retrospective CT-based series supported contrast-enhanced CT for mapping obstruction and excluding urgent complications, but no diagnostic meta-analysis was possible. For medical versus procedural treatment, medical management was associated with lower morbidity (OR 0.16, 95% CI 0.07–0.39) and shorter length of stay (MD − 9.48 days, 95% CI − 12.65 to -6.32), while success, mortality, and overall survival remained inconclusive. For surgery versus endoscopy, surgery showed higher clinical success (OR 2.57, 95% CI 1.47–4.50), whereas endoscopy shortened hospital stay (MD 3.35 days, 95% CI 1.46–5.23); mortality did not differ (OR 1.02, 95% CI 0.70–1.49). Among surgical options, resection showed a signal toward higher perioperative mortality than bypass or ostomy (OR 3.55, 95% CI 1.45–8.68; ). Endoscopic stenting showed a pooled clinical success rate of 0.71 (95% CI 0.62–0.79), whereas evidence on LAMS was limited to one retrospective study. All guideline statements reached 100% agreement among voting participants. Despite the low certainty of available evidence, integration of systematic review findings with expert consensus provides a structured international framework to support decision-making in emergency presentations of PSM-related MBO. These consensus-based recommendations are intended to assist clinicians in harmonizing care across peripheral and referral hospitals, while emphasizing individualized multidisciplinary judgement and the need for future higher-quality evidence.