The prognostic implications of low serum CA 125 levels prior to the second-look operation for stage III and IV epithelial ovarian cancer.

Second-look laparotomy is performed to evaluate response to chemotherapy and to determine the need for additional treatment. The relationship between absolute levels of serum CA 125 less than 35 u/ml and disease status at second-look operation was evaluated in 95 patients with advanced-stage epithelial ovarian cancer. Eighty-six patients had Stage III disease and nine patients had Stage IV cancer. Residual tumor was documented at second-look laparotomy in 52 (55%) of the patients studied. Forty-nine percent of the 82 patients with serum CA 125 values less than 20 u/ml had residual disease. In contrast, 12 of 13 (92%) patients with serum CA 125 values of 20-35 u/ml had residual tumor at second-look laparotomy. All patients with serous cystadenocarcinomas and serum CA 125 values of 20-35 u/ml had residual tumor, and two-thirds of these cases had grossly visible disease. The positive predictive value of a serum CA 125 level of 20-35 u/ml was 0.92. These data suggest that second-look laparotomy should be deferred in patients with advanced-stage ovarian cancer until serum CA 125 values are less than 20 u/ml.