Increased serum cancer antigen-125 is a marker for severity of deep endometriosis

STUDY OBJECTIVE: To determine whether cancer antigen-125 (CA-125) levels are increased in women with endometriosis, especially in those with endometriomas (OMAs), deep infiltrating lesions (DIE), and superficial endometriosis (SUP) compared with controls without endometriosis in a large cohort of operated women. DESIGN: Cross-sectional study (Canadian Task Force classification II-2). SETTING: Tertiary-care university hospital. PATIENTS: Four hundred six women with histologically proven endometriosis and 279 women without endometriosis. INTERVENTIONS: Surgical examination of the abdomino-pelvic cavity. MEASUREMENTS AND MAIN RESULTS: Preoperative serum CA-125 antigen levels were evaluated by electrochemoluminescence immunoassay in women with endometriosis and controls. Correlations between serum CA-125 levels and clinical and anatomical characteristics of disease severity were examined. Women with endometriosis displayed higher mean serum CA-125 levels compared with disease-free controls (50.1 ± 62.4 U/mL vs 22.5 ± 25.2 U/mL; p ≤ .001). CA-125 levels were significantly increased in women with OMA (60.8 ± 63.5 U/mL) and DIE (55.2 ± 68.7 U/mL) compared with women with SUP (23.2 ± 24.5 U/mL) and controls (22.5 ± 25.2 U/mL). There was no difference in CA-125 levels between patients with SUP and controls and between patients with OMA and DIE. CA-125 serum levels were correlated with DIE severity: the mean number of DIE lesions and worst DIE lesion. CONCLUSION: Serum CA-125 levels were significantly increased in women with severe forms of endometriosis, OMA, and DIE lesions. In addition, elevated serum Ca-125 levels were associated with more severe and extended DIE lesions. In women with superficial peritoneal lesions, CA-125 levels were not different from women without endometriosis.