OVX1, macrophage-colony stimulating factor, and CA-125-II as tumor markers for epithelial ovarian carcinoma: a critical appraisal

Background: Ovarian carcinoma remains the leading cause of death from gynecologic malignancy in Australia, the Netherlands, and the United States. CA-125-II, the most widely used serum marker, has limited sensitivity and specificity for detecting small-volume, early-stage disease. Therefore, a panel of three serum tumor markers-OVX1, CA-125-II, and macrophage-colony stimulating factor (M-CSF)-has been used to evaluate the sensitivity and specificity of multiple markers for the detection of early-stage ovarian carcinoma.

Methods: Preoperative serum levels of OVX1, CA-125-II, and M-CSF were measured in 281 patients with primary ovarian epithelial tumors of different histotypes. Among these tumors, 175 were malignant, 29 were of borderline malignancy, and 77 were benign. The three markers also were measured in sera from 117 apparently healthy women. Marker levels were considered abnormal at CA-125-II > 35 U/mL, OVX1 > 7.2 U/mL, and M-CSF > 3.5 ng/mL.

Results: Among 175 women with malignant ovarian tumors, at least one of the three serum markers was elevated in 85%, whereas CA-125-II was elevated in 80% (P = 0.008). In 58 patients with Stage I ovarian carcinoma, at least one of the three serum markers was elevated in 76%, whereas CA-125 levels were elevated in 66% (P = 0.04). For patients with borderline and benign tumors, a combination of the three antigens had slightly higher sensitivity compared with CA-125-II, but the differences were not statistically significant. Among 117 apparently healthy women, CA-125-II was elevated in 4%, and one of the three markers was positive in 17%.

Conclusions: The sensitivity of a combination of three serum markers was significantly greater than the sensitivity of the CA-125-II assay alone in patients with primary ovarian epithelial tumors of different histotypes. This was true for all stages, including early-stage, potentially curable disease. When used as single markers, however, only the CA-125-II assay could distinguish invasive Stage I tumors from apparently healthy women.