Consensus Guideline for the Management of Colorectal Cancer with Peritoneal Metastases

Background: The peritoneum is a common site of metastases from colorectal cancer (CRC), yet controversy exists regarding optimal treatment strategies. These guidelines describe the results of a national consensus addressing the management of CRC with peritoneal metastases (CRC-PM). Methods: An update of the 2018 Chicago Consensus Guidelines was conducted using a modified Delphi technique. Two rounds of voting were performed to assess agreement levels on two clinical management pathways regarding synchronous and metachronous CRC-PM. Supporting evidence was evaluated via rapid literature reviews. Results: The overall level of evidence was low in existing literature. Of 145 participants in the first round, 136 (96.8%) responded in the second round. Over 90% consensus was achieved in most pathway blocks. For both pathways, early referral to a peritoneal surface malignancy (PSM) center should be made for patients with CRC-PM. For the synchronous pathway, upfront cytoreductive surgery was de-emphasized in favor of systemic therapy. For the metachronous pathway, risk stratification via clinical and pathologic features was revised. For both pathways, surveillance strategies were added, including only a weak recommendation for circulating tumor DNA (ctDNA) testing given limited evidence of its utility in detecting and monitoring PM. Conclusion: The consensus-driven clinical pathways provide valuable guidance for the management of CRC-PM. There remains a need for high-quality evidence and prospective multicenter trials in this domain.