Monitor the course of ovarian cancer, patient response to treatment, and disease recurrence. Serum CA 125 concentrations are elevated in about 80% of women with carcinoma of the ovary, 26% of women with benign ovarian tumors and 66% of women with non-neoplastic conditions, but in only 3% of normal healthy women. CA 125 should not be used alone to diagnose or screen for cancer, but it is useful for monitoring patients with an established diagnosis of a gynecological malignancy that is associated with elevated CA 125 at diagnosis.