Management of colorectal cancer patients at high risk of peritoneal metastases.

PURPOSE Colorectal cancer (CRC) has potential to spread within the peritoneal cavity, and this transcoelomic dissemination is termed "peritoneal metastases" (PM). Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is a radical strategy to treat selected CRC patients with PM. Studies suggest that identification of CRC patients at high risk of PM may lead to earlier treatment strategies and improve survival in this subset of patients. The aim of this article was to summarise the current evidence regarding CRC patients at high risk of PM. METHODS A retrospective review of articles on CRC patients with high risk of PM published up to December 2014 in PubMed, Medline, Embase, and Ovid search engines was conducted. The following combination of search terms were used: "intraperitoneal chemotherapy", "HIPEC", "colorectal cancer", "peritoneal carcinomatosis", "peritoneal metastases", "high risk", "peritoneal recurrence". RESULTS Although opinions differ, CRC patients identified as "high risk" of PM included: limited, synchronous PM completely resected with the primary tumor, ovarian metastases (synchronous or metachronous) and spontaneous or iatrogenic perforation of the bowel by the primary tumor. Aggressive early treatment strategies currently used are: CRS and HIPEC for high-risk primary tumors and second-look CRS and HIPEC often following systematic chemotherapy for the primary resection. Positive results have been shown with both approaches in a number of studies. With CRS/HIPEC for the primary tumor, the overall survival in the two groups (25 patients treated with CRS/HIPEC vs 50 treated with conventional surgery) was significantly improved (p<0.03), as was disease-free survival (p<0.04). For second look surgery, in 29 patients treated with CRS and HIPEC, this resulted in 14% morbidity and 0% mortality and a 2-year disease-free survival rate in excess of 50%. CONCLUSIONS We are progressively moving to an era of individualised treatment strategies. The management of CRC patients with high risk of PM is ever evolving, with early detection and early treatment strategies showing promising results. The optimal timing of early surgery remains unclear and requires further evaluation. Should current and future randomized trials demonstrate long-term survival benefit, we may potentially see a change in treatment paradigm from current conventional surgery to a more aggressive, early radical approach as the standard of care.