Background: Selecting colorectal patients for HIPEC-surgery needs improvement. The study aim was to improve the colorectal peritoneal score (COREP) and to compare it with three other scores: peritoneal-surface disease-severity score (PSDS), colorectal-peritoneal metastases prognostic-surgical-score (COMPASS), and the CEA/PCI ratio.
Method: Twelve preoperative factors were chosen to evaluate for COREP score modification. Criteria from logistical analyses were set to qualify for the modified COREP score (mCOREP). Odds ratios were used to assign score points for the eligible factors with open/close laparotomy prediction as endpoint. mCOREP was applied internally and compared with the original COREP, PSDS, COMPASS, and CEA/PCI ratio. Odds ratios, hazard ratios, and Kaplan-Meier curves were used for comparison.
Results: Seven factors qualified for mCOREP: CEA, CA 19-9, CA-125, C-reactive protein, albumin, platelet count and signet-cell histology. mCOREP was superior to the original COREP. mCOREP and COMPASS scores were the only scores with independent prognostic value. The mCOREP had the best discriminatory ability between its prognostic groupings. mCOREP 11 + had 9 months survival with half of patients being open/close surgery.
Conclusion: The mCOREP has successfully been simplified while still improving its prognostic ability. The mCOREP and COMPASS scores have independent prognostic value. Patients with mCOREP 11 + may not benefit from treatment.
Keywords: Colorectal cancer; cytoreductive surgery; hyperthermic intraperitoneal chemotherapy; patient selection; peritoneal metastases; prognosis.