Value of cancer antigen 125 for diagnosis of pleural endometriosis in females with recurrent pneumothorax.

The thorax is the most frequent extrapelvic location of endometriosis. Thoracic endometriosis is probably responsible for the high rate of recurrent pneumothoraces in females. The goal of the present prospective study was to assess the value of cancer antigen (CA)125 measurement in the detection of endometriosis in order to further enable early and adequate treatment of catamenial pneumothorax. Between January 2004 and March 2006, 31 females (mean age 32 yrs) underwent pneumothorax surgery. The control group comprised 17 males (mean age 27 yrs), who underwent videothoracoscopic pleural abrasion. Serum CA125 was measured around a menstrual period in females and before surgery in males. Videothoracoscopically diagnosed endometriosis occurred in 29% of females. The CA125 concentration was significantly higher in females with endometriosis compared to disease-free females (76.1 versus 16 U x mL(-1)). The mean value in males was similar to that observed in disease-free females. The frequency of thoracic endometriosis-related pneumothorax corresponds to, on average, a third of females presenting with recurrent pneumothorax. Early detection can be achieved with serum cancer antigen 125 measurement and may be helpful in indicating videothoracoscopic surgery.