The CA 125 assay as a predictor of clinical recurrence in epithelial ovarian cancer.

Serum CA 125 levels were obtained from 55 women with epithelial ovarian cancer before a second-look surgical procedure and serially thereafter. All patients were clinically and radiographically free of tumor at the time of the second-look operation and were followed to clinical recurrence. Median follow-up was 12 months. CA 125 levels obtained at the second-look operation had a sensitivity and specificity for predicting clinical recurrence of 94% and 88%, respectively. Patients with an elevated CA 125 level (greater than or equal to 35 U/ml) had a 60% chance of clinical recurrence within 4 months, while patients with levels less than 35 U/ml had a 5% chance of clinical recurrence over the same time period. Serial CA 125 levels obtained after second-look operations were strong predictors of clinical outcome, and distinctly different monitoring profiles were observed among those patients remaining clinically free of tumor and those suffering clinical recurrence. The CA 125 assay became elevated (greater than or equal to 35 U/ml) before clinical recurrence in 94% of 35 cases with a median lead time of 3 months. The CA 125 assay identifies patients destined to suffer a clinical recurrence and provides a warning measurable in months. This may have important implications for therapy.