Colorectal peritoneal metastases treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: Should we consider the primary tumour site?

BACKGROUND

Several publications have shown that cancers of the colon and of the rectum are significantly different, and tumor location is a major prognostic factor for survival. However, colorectal peritoneal metastases (CRPM) is still considered as a homogeneous and a single disease without differentiating between colonic or rectal origin. We asked whether the primary tumor location influences the survival and surgical outcomes of patients with colonic (C_PM) and rectal peritoneal metastases (R_PM) following cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

Between January 2013 and March 2024, data from 1237 CRS/HIPEC procedures in 1152 patients with CRPM were analysed (C_PM, n = 1129; R_PM, n = 108). Overall survival (OS), recurrence-free survival (RFS), and day-30 morbi-mortality were compared.

RESULTS

The 3-year and 5-year OS rates were 68.9% and 52.5% respectively and were significantly better for C_PM than for R_PM patients: (69.8% vs 61%; p = 0.036) and (53.4% vs 43.6%; p = 0.031) respectively. Stratification according to left (LC_PM) and right colonic (RC_PM) subgroups resulted in better 3-year OS for LC_PM than for RC_PM (73.9% vs 63.2%; p ≤ 0.001). Multivariate analysis of 5-year survival identified PCI >15 (HR = 2.09), R_PM (HR = 1.46) and RC_PM (HR = 1.29) as significant risk factors of death. The C_PM group had fewer re-interventions at day-30 (17.6% vs 36.1%; p ≤ 0.001) and shorter surgery time (330 vs 390 min; p ≤ 0.001), ICU-stay (3 vs 4 days; p ≤ 0.001) and hospital length-of-stay (14 vs 17 days; p = 0.002).

CONCLUSION

Patients presenting with colonic PM have significantly better OS at 3 and 5 years with fewer re-interventions at day-30 and, shorter surgery time, ICU and hospital stay than those presenting rectal PM. Left-side colonic PM has a significantly better OS at 3-years than right-side colonic PM. PCI >15, rectal and right colonic origin are linked to earlier mortality. When deciding on CRS/HIPEC treatment, designing a study, or reporting data, the CRPM primary tumour site should be taken into account.