CA 125 for the monitoring of ovarian carcinoma during primary therapy.

Thirty-one patients with ovarian cancer were monitored with the CA 125 antigenic determinant in the interval between cytoreductive surgery and the completion of subsequent chemotherapy. Distinct CA 125 assay trends have emerged from prospective serial monitoring. Among patients who were clinically and surgically free of disease after the completion of cytoreductive chemotherapy, the CA 125 assay always fell to levels under 35 U/mL within the first three months of cytoreductive chemotherapy, and stayed at low levels. Patients with partial cytoreduction operations had decreases in serum CA 125 levels only if there was a response to further therapy. The rate of fall of the CA 125 levels correlated with clinical outcome. All 13 patients with serum CA 125 above 35 U/mL after three months of treatment invariably had persistent tumors after subsequent chemotherapy, whereas in patients showing reduction of the CA 125 to levels below 35 U/mL, there were no surgically detectable tumors. Measurement of CA 125 during treatment might permit an early change to alternative and optimal forms of therapeutic management. The CA 125 level three months after treatment appears to be a critical predictor of response to therapy.