The epidemiology, current evidence and controversies in diagnosis and management of patients with colorectal peritoneal metastases.

BACKGROUND

Peritoneal metastases (PM) are a common site of spread in colorectal cancer (CRC) and are associated with poor survival outcomes. The true burden of disease is difficult to quantify due to limitations in imaging and limited symptoms until advanced disease. Systemic therapy has limited benefits and there is an increasing interest in the use of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). This narrative review summarises the current literature on epidemiology of PM in CRC and evidence based current management strategies.

METHODS

PubMed was search for the terms "Peritoneal Metastases" or "Peritoneal carcinomatosis" and "Colorectal Cancer" from inception to December 2024. Titles of all English language articles were considered and backwards referencing screening was undertaken in key articles. Inclusion criteria included all original articles with a focus on the clinical management of PM and CRC.

FINDINGS: PM occur in 5-10 % of patients with CRC. The current literature likely underestimates the true burden of disease due to reliance on accurate registry data, and little is published on UK data. Systemic therapy has limited benefit in patients with PM. The PRODIGE-7 trial highlighted the benefits of CRS in select patients but raised questions about the benefits of HIPEC. Prophylactic HIPEC remains controversial but the findings of HIPECT4 show promising results.

CONCLUSION

The true burden of PM and CRC remains unclear particularly in the UK population. CRS has clear benefits in patients that undergo complete cytoreduction. Further work is required to determine the benefits of HIPEC and how to optimise this for patients.