The relationship between postoperative decline of serum CA 125 levels and size of residual disease after initial surgery in patients with advanced ovarian cancer: a CTF study.

This retrospective study assessed 46 patients with advanced ovarian cancer who had elevated preoperative serum CA 125 (>35 U/ml) and who had another serum CA 125 assay 6-9 days after surgery. Preoperative CA 125 levels were similar in patients with residual disease below 20 mm and in those with larger residuum. The postoperative decline of serum CA 125 was significantly higher in patients with small residual disease at any preoperative serum CA 125 value. By taking 60% as the cutoff of CA 125 decline, the diagnostic accuracy of this parameter in discriminating between patients with residual disease below or above 20 mm improved progressively when we considered patients with increasing preoperative antigen values. However, even in the subset of patients with preoperative serum CA 125 above 400 U/ml, 2 of the 20 patients with less than 20 mm residual disease had a percentage reduction of antigen levels lower than 60%, whereas 5 of the 10 patients with larger than 20 mm residuum had a CA 125 decline higher than 60%. Therefore, we believe that the perioperative changes of CA 125 levels have a limited clinical relevance in the management of patients with ovarian cancer.