Serum CA-125 and 17 beta-estradiol in patients with external endometriosis on danazol

Serum concentration of CA-125 and 17 beta-estradiol (E2) were measured by radioimmunoassay in 40 patients with stage III or IV endometriosis to evaluate their usefulness in assessing the outcome of disease. Patients were categorized into good responders and poor responders depending on the result of the second-look laparoscopy 8 weeks after danazol therapy. CA-125 decreased significantly in all subjects after initiation of treatment. However, after 12 weeks of treatment a significant increase (p less than 0.05) in serum CA-125 was noted in the poor-response subjects as compared to the good-response subjects. In addition, 8 weeks after treatment CA-125 levels in the poor-response group were significantly higher (p less than 0.001) than in the good-response group. On the other hand, in the good-response group, E2 levels decreased for 8 weeks during danazol therapy to return to almost basal levels after 12 weeks, while in the poor-response group E2 levels did not change as compared to pretreatment levels. We conclude that the determination of CA-125 and E2 may be helpful in assessing the response of patients with advanced endometriosis on danazol treatment.