Does the primary tumour location affect the prognosis of patients with colorectal cancer peritoneal metastases treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy?

Background The impact of primary tumour location on the prognosis of patients with peritoneal metastasis (PM) arising from colorectal cancer (CRC) after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is rarely discussed, and the evidence is still limited. Methods Patients with PM arising from CRC treated with CRS and HIPEC at the China National Cancer Center and Huanxing Cancer Hospital between June 2017 and June 2019 were systematically reviewed. Clinical characteristics, pathological features, perioperative parameters, and prognostic data were collected and analysed. Results A total of 70 patients were divided into two groups according to either colonic or rectal origin (18 patients in the rectum group and 52 patients in the colon group). Patients with PM of a colonic origin were more likely to develop grade 3-4 postoperative complications after CRS+HIPEC (38.9% vs 19.2%, P = 0.094), but this difference was not statistically significant. Patients with colon cancer had a longer median overall survival (OS) than patients with rectal cancer (27.0 vs 15.0 months, P = 0.011). In the multivariate analysis, the independent prognostic factors of reduced OS were a rectal origin (HR 2.15, 95% CI 1.15-4.93, P = 0.035) and incomplete cytoreduction (HR 1.99, 95% CI 1.06-4.17, P = 0.047). Conclusion CRS is a complex and potentially life-threatening procedure, and we suggest that the indications for CRS+HIPEC in patients with PM of rectal origin be more restrictive and that clinicians approach these cases with caution.