Patient selection for cytoreductive surgery in colorectal peritoneal carcinomatosis using serum tumor markers: an observational cohort study.

ABSTRACT

OBJECTIVE: There were 2 objectives: first, to investigate how many patients were excluded from surgery on the basis of the radiological extent of the peritoneal carcinomatosis (PC) or the clinical examination; and second, to develop a score based primarily on serum tumor markers (STMs) that could predict short cancer-specific survival (<12 months). BACKGROUND: Patient selection and prediction of prognosis is crucial for successful treatment of colorectal PC. METHODS: All patients with colorectal PC referred for cytoreductive surgery and intraperitoneal chemotherapy (2005-2008) at Uppsala University hospital were included. Patients were divided into 2 groups-nonsurgery and surgery. Clinicopathological and laboratory parameters were collected in the surgery group. A Corep (COloREctal-Pc) score was developed using hazard ratios from histology, hematological status, serial serum tumor markers (STMs), and STM changes over time. Sensitivity, specificity, positive predicted value (PPV), and negative predicted value (NPV) were calculated in a second validating dataset (n = 24) with a survival cutoff of less than 12 months. RESULTS: A total of 107 patients were included in the study, 42 in the nonsurgery group and 65 in the surgery group. In the nonsurgery group, 2 patients were excluded solely on the basis of the radiological extent of PC and 7 patients on clinical examination. The Corep score ranged from 0 to 18. A score of 6 or more showed a validated sensitivity of 80%, specificity 100%, PPV 1.0, and NPV 0.93. CONCLUSIONS: Radiological extent of PC was not a main deciding factor for treatment decisions and had less impact than the clinical examination. The Corep score identified patients with short cancer-specific survival that may not be suitable for treatment.