The value of CA 125 determination in the serum of patients with ovarian cancer

The circulating ovarian cancer associated antigen CA 125 was determined in serum of 63 patients with ovarian malignancies by radioimmunometric solid phase assay using the monoclonal antibody OC 125 as catcher and tracer. The results of 41 patients with 43 active tumour situations were compared with the CA 125 serum levels of 27 patients without recurrence after therapy of ovarian cancer and 49 benign ovarian tumours. Significant differences exist between these three groups (p less than 0.001) with elevated values (greater than 35 U/ml) in 84 per cent in ovarian carcinoma, 22 per cent in benign tumours and nought per cent in woman without recurrence in follow-up. The pre-operative sensitivity in ovarian cancer is 93 per cent (in epithelial carcinoma 96 per cent) with a distinct dependence of the CA 125 serum levels on the stage of the disease (stage III and IV versus stage I and II; p less than 0.01). A positive correlation of CA 125 values to clinical status was found in 82 per cent in follow-up. Increasing values of CA 125 can detect the recurrence any months earlier than the clinical examination. Decreasing serum levels in chemotherapy don't reflect the objective tumour remission in every case. Because of elevated values in benign and inflammatory adnexal tumours and the relative low sensitivity in borderline cases (three of seven patients greater than 35 U/ml) the CA 125 assay seems not be suitable for a screening method. However it is a substantial amplification in control of therapeutic success and an early detection of recurrence of ovarian cancer disease.