Serum CA-125 concentration in endometriosis patients: role of pelvic and peritoneal irritation

Serum CA-125 concentrations were investigated preoperatively in 91 consecutive women undergoing laparoscopy for infertility, pelvic pain and/or annexial cysts. The presence and extent of endometriosis were carefully assessed, including the American Fertility Society stage of disease, and implant and adhesion scores. Postoperative CA-125 measurements were obtained in 32 of 53 endometriosis patients and evaluated with respect to clinical evolution of the disease. Serum levels of CA-125 were significantly increased in patients with endometriosis (46.5 +/- 39.5 vs. 13.5 +/- 7.3 U/ml in controls, p < 0.001) and correlated with the severity of disease. A positive correlation (r = 0.7, p < 0.001) was observed between adhesion score and CA-125 levels, while the relationship with implant score was not significant (r = 0.3, p = 0.07). CA-125 level was also significantly increased in women with peritoneal endometriosis (70.7 +/- 47.3 vs. 33.5 +/- 25.6 U/ml for those with ovarian endometriosis), and in these patients the post-operative CA-125 level was significantly related to the clinical evolution of the disease, being higher in patients whose disease recurred compared to those with negative follow-up, irrespective of the adhesion score. We conclude that in endometriosis patients, serum CA-125 level is directly related to the adhesion score and peritoneal involvement, suggesting a central role of pelvic and peritoneal irritation in the increased level of this serum marker.