Serum CA 125 as a marker for patients with external endometriosis.

Serum CA 125 levels were assayed in 75 healthy female controls and 34 patients with external endometriosis prior to treatment, during treatment, and after treatment. The results of the assay showed that the mean pretreatment serum CA 125 level of the patients with external endometriosis (80.7 U/mL) was significantly (P less than .001) higher than that of the controls (17.9 U/mL). This difference was even more pronounced for those patients with progressive (stage III or IV) endometriosis (mean = 114.0 U/mL). Thus, the assay of serum CA 125 may be useful as an auxiliary tool in the diagnosis of progressive endometriosis. Although the high pretreatment level of serum CA 125 decreased after danazol treatment of 400 mg/day to within the normal limits, usually within 4 to 12 weeks, laparoscopic examinations indicated that most of the endometriosis cases were not cured until 12-16 weeks of danazol treatment.