Significance of a single CA 125 assay combined with ultrasound in the early detection of ovarian and endometrial cancer.

We evaluated the utility of a single CA 125 measurement in combination with transvaginal sonography for early detection of ovarian and endometrial cancer in asymptomatic postmenopausal women. A sample of peripheral blood was taken from 1291 apparently healthy postmenopausal women, who were examined by conventional and color Doppler ultrasound for early detection of ovarian and endometrial cancer. Serum CA 125 was determined in all samples 3 years later by the IMx CA 125 assay (Abbott Laboratories, Abbott Park, IL). The cutoff level based on the 99th percentile was 30 U/ml. Elevated values were controlled by repeat sonography and an additional determination of CA 125. Record linkage with the files of the Finnish Cancer Registry was performed 3 1/2 years after the primary sonographic screening. The mean CA 125 concentration was 8.1 U/ml (range 0-1410 U/ml). Fourteen of the 1291 women had a CA 125 level greater than 30 U/ml. None of these had signs of either endometrial or ovarian malignancy in the primary sonography screening. Among the other women three cases of endometrial carcinoma (all stage Ib) and one ovarian carcinoma (stage Ia with borderline malignancy) were detected by sonography. All these patients had a CA 125 value <30 U/ml, the mean value being 11.4 U/ml (range 7.5-16.7 U/ml). During follow-up of 3.5 years, one stage Ia ovarian carcinoma, one abdominal carcinomatosis, and two endometrial carcinomas (both stage Ib) were diagnosed. In these patients the mean value for CA 125 was 12.7 U/ml (range 2.5-30.9 U/ml) at the primary sonography screening. A single CA 125 measurement provides no advantage in the early detection of ovarian and endometrial cancer in asymptomatic postmenopausal women compared with transvaginal sonography. The vast majority of women with an elevated CA 125 value have some reason other than an ovarian or endometrial malignancy for this finding.