Predictive value of CA 125 during early chemotherapy of advanced ovarian cancer.

CA 125 was measured during early chemotherapy of 61 patients with epithelial ovarian carcinomas (FIGO stages III and IV) to determine if patients with a poor response to further treatment could be identified during early therapy. Blood samples were drawn before the start of chemotherapy and 1 month after the first, second, and third courses. Prior to therapy all patients had increased CA 125 levels, but 77% (47/61) had normal antigen levels after the third course. Second-look laparotomy was performed 4-10 months after the third course; 24 patients had no evidence of disease (NED) and 37 had residual tumor (RT). After three courses of chemotherapy, NED patients all had normal CA 125 values, whereas 38% (14/37) of the RT patients had increased antigen levels. In conclusion, increased CA 125 values after the third course of chemotherapy identified 38% of the patients who responded insufficiently to further therapy. Treatment in progress should here be stopped and replaced by palliative therapy if other curative regimens are considered nonexistent. Normal CA 125 values had no predictive value owing to the many (62%) false-negative antigen values.