Combination of cancer antigen 125 and carcinoembryonic antigen can improve ovarian cancer diagnosis.

Introduction: The purpose of the present study was to evaluate the ability of the tumour marker carcinoembryonic antigen (CEA) in combination with cancer antigen 125 (CA-125) to differentiate between malignant ovarian and malignant non-ovarian disease.

Material and methods: All patients attending the Department of Gynaecology, Herlev Hospital, who underwent an "ovary lab investigation" between 1 January 2006 and 31 December 2008 were included. Among a total of 640 patients, 355 had a malignant diagnosis. Preoperative CEA and CA-125 serum levels and final malignant diagnosis after surgery were extracted from the medical records.

Results: Among the patients with CEA levels > 5 ng/ml, 68% had non-ovarian malignancies. This test identified 39% of the non-ovarian cancers correctly. In patients with a CA-125/CEA ratio > 25, an ovarian cancer was found in 82%. The CA-125/CEA test identified 63% of the non-ovarian cancers correctly. The specificity increased to around 85% when the cut-off value of the CA-125/CEA ratio was increased from 25 to 100.

Conclusion: In patients with an undiagnosed tumour in the pelvis, the CA-125/CEA ratio may be used to preoperatively identify a substantial fraction of patients with non-ovarian malignancies. In the study population, the specificity rose to 85% when the cut-off value was increased from 25 to 100, which highlights the usefulness of a higher cut-off level.

Funding: not relevant.

Trial registration: not relevant.