Evaluation of serum CA 125 levels in the monitoring of ovarian cancer.

Serum CA 125 levels were evaluated in 227 patients with ovarian cancer. CA 125 levels were elevated in 86% of the patients. All histologic types, including mucinous tumors, were associated with raised CA 125 levels. There was a positive correlation with tumor burden and an inverse correlation with degree of differentiation. In patients undergoing radical operation an elevated CA 125 level was a bad prognostic index. Serial CA 125 measurements were assessable in 112 patients undergoing chemotherapy. Rising or falling levels correlated with disease in 92% of the cases. The CA 125 level increased before clinical progression with a median lead time of 3 months. Only patients who showed objective response to chemotherapy had a decrease in antigen levels of greater than or equal to 30% 4 weeks after the first course of chemotherapy and a normalization of CA 125 levels 3 months after initiation of chemotherapy. Rising levels were always associated with progression. These data suggest that CA 125 may aid in early identification of nonresponders. However, a normal CA 125 level does not exclude the presence of disease.