Clinical Relevance of the CA 125 Assay in Monitoring of Ovarian Cancer Patients

CA 125 levels were measured longitudinally during treatment and follow-up of 248 epithelial ovarian cancer patients referred to the Department of Gynecological Oncology at Radiumhemmet, Stockholm, from 1984 to 1986. The aim of the study was to evaluate the value of CA 125 monitoring in clinical practice according to tumor burden at the time of referral to Radiumhemmet, the correlation of CA 125 values to tumor mass at second-look laparotomy, the lead time between increasing CA 125 values and tumor relapse, and the predictivity of normal CA 125 values after completion of first-line therapy. Ninety-one percent (32/35) of patients with a tumor volume greater than 5 cm at referral had elevated CA 125 values; 62% (22/35) with no tumor mass had normal CA 125 values. Elevated CA 125 values greater than 35 U/ml before second-look laparotomy predicted remaining tumors in 77% (15/19) of patients. The mean lead time between increasing CA 125 values and tumor relapse was 3 months. Normal CA 125 values at the end of first-line therapy may predict long survival times.