The Ability of Preoperative Serum CA-125 to Predict Optimal Primary Tumor Cytoreduction in Stage III Epithelial Ovarian Carcinoma

Purpose. The aim of this study was to determine the ability of preoperative serum CA-125 to predict optimal primary tumor cytoreduction in patients with Stage III epithelial ovarian carcinoma. Methods. We performed a retrospective chart review of 100 consecutive patients with Stage III ovarian carcinoma who had a serum CA-125 drawn prior to primary cytoreductive surgery. We used a receiver operating characteristic curve to determine the CA-125 level with the maximal prognostic power in predicting optimal versus suboptimal cytoreduction. Results. The median CA-125 level for the 100 patients was 819 U/ml (range 5.6–26,200 U/ml). Optimal cytoreduction (diameter of largest residual tumor nodule ≤1 cm) was obtained in 45 cases (45%). The probability of performing optimal cytoreduction decreased with increasing CA-125 levels. A preoperative CA-125 level of 500 U/ml was identified as the value with the most predictive power. Optimal cytoreduction was achieved in 33 of the 45 cases (73%) with a CA-125 less than 500 U/ml compared to only 12 of the 55 cases (22%) with a CA-125 greater than 500 U/ml. Using a threshold level of 500 U/ml, the preoperative serum CA-125 level was able to predict optimal versus suboptimal cytoreduction with a sensitivity of 78%, specificity of 73%, positive predictive value of 78%, and negative predictive value of 73%. Conclusion. The probability of performing optimal cytoreduction in patients with Stage III ovarian carcinoma and a preoperative CA-125 greater than 500 U/ml was approximately one in five. These patients may be candidates for initial laparoscopic evaluation to obtain a confirmatory tissue diagnosis and to determine resectability.