Raised Serum Tumour Markers Predict Incomplete Cytoreduction, Disease-Free and Overall Survival in Patients with Colorectal Peritoneal Metastases Treated by Cytoreductive Surgery and HIPEC.

[BACKGROUND] Raised serum tumour markers are a prognostic factor in advanced colorectal cancer. The purpose of the current study was to evaluate the role of elevation of carcinoembryonic antigen (CEA), cancer antigen 125 (CA 125) and carbohydrate antigen (CA 19.9), with a focus on burden of peritoneal disease, incomplete cytoreduction, and survival in patients with colorectal peritoneal metastases (CPM) treated by cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

[METHODS] This is a retrospective analysis of a prospectively collected database. Patients with CPM treated by CRS and HIPEC in a single high-volume centre between 2000-2021 with complete demographic, tumour marker status, histopathological, and follow-up information were included.

[RESULTS] In total, 433 patients were included, of which 232 (53.6%) were female. The median age was 59 years, and the median peritoneal cancer index (PCI) was 6. Overall, 268/433 (61.9%) patients had one or more elevated tumour markers. Elevated tumour markers were associated with higher PCI and higher risk of receiving incomplete cytoreduction (odds ratio [OR] 2.8, p = 0.026 and OR 6.21, p < 0.001 for two and three elevated markers, respectively). Furthermore, elevated tumour markers were associated with worse 5-year overall survival (overall survival, hazard ratio 1.55, p = 0.021; 2.85, p < 0.001; and 2.85, p < 0.001 for any one, any two, or all three elevated markers, respectively) and disease-free survival at multivariable analysis.

[CONCLUSIONS] Elevated preoperative tumour markers correlate with extent of CPM, a higher risk of incomplete cytoreduction, and decreased overall survival and disease-free survival.