Consensus guideline for the management of colorectal cancer with peritoneal metastases

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). An update of the 2018 Chicago consensus guidelines was conducted with 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. The overall level of evidence was low in the 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 center should be made for patients with CRC-PM. For the synchronous pathway, upfront cytoreductive surgery was deemphasized in favor of systemic therapy. For the metachronous pathway, risk stratification via clinical and pathological features was revised. For both pathways, surveillance strategies were added, including only a weak recommendation for circulating tumor DNA testing, given limited evidence of its utility in detecting and monitoring PM. 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.