Serum CA 125 levels and surgical findings in patients undergoing secondary operations for epithelial ovarian cancer

Serum CA 125 levels and surgical findings were prospectively compared in 96 secondary laparotomies performed on patients with epithelial ovarian cancer. All patients had documentation of an elevated CA 125 level (greater than 35 U/ml) at a time when ovarian cancer was present, and thus the tumors were known to be "marker positive." Operation was performed in 45 patients who were clinically free of disease and in 51 patients in whom there was clinical evidence of disease. At the time of operation, 29 patients had normal CA 125 levels; persistent disease was documented in 18 (62%) of these. Of the patients with normal CA 125 levels at the time of operation, those with persistent disease had a significantly higher mean CA 125 level (16.9) than those with no disease detected (8.8, p = 0.001). At exploration, cancer was found in 84 patients. There was a correlation between the maximum diameter of the largest residual tumor mass and the accuracy of the CA 125 level as follows: microscopic to 1 cm disease, 55% accuracy; greater than 1 to 5 cm disease, 80% accuracy; greater than 5 cm disease, 92% accuracy (p = 0.013). There was no correlation of CA 125 accuracy with the patient's age, number of months from initial diagnosis, tumor stage, grade, or cell type, or the highest-ever level of CA 125. Of the 84 patients with tumor found at exploration, 66 had elevated CA 125 levels, yielding a sensitivity of 78.5%. There were 12 patients with no tumor found at exploration; 11 of these had normal CA 125 levels. The one patient who had an elevated CA 125 level subsequently had a recurrence; the corrected specificity is thus 100%. An elevated CA 125 level is an accurate predictor of persistent disease. Most of these patients will have gross tumor present. The accuracy of the CA 125 level in detecting disease is related to the amount of tumor present. In our population, the predictive value of an elevated CA 125 level was 100%; the predictive value of a normal CA 125 level was 38%.