Clinical utility of serum tumor markers in the diagnosis of malignant intestinal occlusion. A prospective observational study.

AIM: The aim of the present observational study was to evaluate the diagnostic accuracy of CEA, CA 19-9 and CA 72-4 in patients with bowel obstruction.
METHODS: One-hundred three patients admitted to an emergency unit with clinical and radiological signs of intestinal occlusion of unknown origin were prospectively studied. Patients submitted to emergency surgery were excluded. All patients underwent standard diagnostic procedures and serological assay of tumor markers.
RESULTS: Colorectal cancer was diagnosed in 22 patients (21.4%), while 81 patients (78.6%) presented a benign condition. The sensitivity of CEA, CA 19-9 and CA 72-4 for colorectal cancer was 36.4%, 31.8% and 9.1%, respectively. Marker specificity was 91.4%, 90.1% and 95.1%, respectively. The combination of CEA and CA 19-9 increased the sensitivity to 45.5% but decreased the specificity to 83.9%. The overall accuracy was 79.6%, 77.7% and 76.7%, respectively. All positive cancer cases had advanced disease. All patients with CEA levels >10 ng/mL or CA 19-9 >100 U/mL had colorectal cancer.
CONCLUSIONS: Even in a highly selected population, tumor marker sensitivity was rather low and specificity incomplete. However, elevated levels may guide the diagnostic and therapeutic course in patients with obstructing colorectal cancer.