CA125 and endometriosis.

This review covers the literature on CA125 and endometriosis; data on CA125 and oncology are not discussed. In normal women, plasma concentrations of CA125 are increased slightly at ovulation and significantly during menstruation. Marked increases are observed during pregnancy and following peritoneal irritation by infection or surgery. These data are consistent with the concept that CA125 in normal women is mainly derived from the endometrium and the irritated peritoneum. Plasma concentrations of CA125 are markedly elevated in women with cystic ovarian endometriosis and/or deeply infiltrating endometriosis, but not, or only slightly, in the luteal phase of women with minimal or mild endometriosis. This is consistent with the recent concept which considers minimal endometriosis as a normal condition occurring intermittently in many women, in contrast with deep endometriosis and cystic ovarian endometriosis which are called 'endometriotic disease'. Serum CA125 is not a good marker for endometriosis but it is a helpful additional parameter to diagnose endometriotic disease in patients with chronic pelvic pain. Following treatment of endometriosis, elevated plasma concentrations of CA125 could be used as an argument that treatment has been incomplete, or that the condition has recurred. Assaying CA125 in peritoneal fluid requires high sample dilutions or a modified immunoradiometric assay, and until now, its clinical value has been questionable.

CA 125 in the management of endometriosis.

CA 125 is expressed by eutopic and ectopic endometrium. In women with advanced endometriosis, plasma concentrations are increased towards the end of the luteal phase and during menstruation but not during the follicular and early luteal phases. In women without endometriosis, such cyclic changes of CA 125 in plasma are not observed. In women with cystic ovarian endometriosis, plasma CA 125 concentrations are markedly elevated. Measurement of CA 125 in ovarian cyst fluid is the method of choice to differentiate a cystic corpus luteum from an ovarian endometriotic cyst, a frequent and difficult clinical problem. CA 125 can be used to diagnose deeply infiltrating endometriosis with a sensitivity of 36% and a specificity of 87%. These figures underestimate the clinical importance, since plasma CA 125 concentrations are mainly important for the diagnosis of deeply infiltrating endometriosis types II and III, which are the most severe forms and which are clinically easily missed. Because of the strong association of deep endometriosis and pelvic pain, the assay of CA 125 in plasma may be advocated in all women with unexplained pelvic pain as an aid in the diagnosis of deeply infiltrating endometriosis. Following surgical excision of endometriosis, CA 125 can be used to monitor the completeness of surgery.

CA 125 concentrations in ovarian 'chocolate' cyst fluid can differentiate an endometriotic cyst from a cystic corpus luteum.

In a prospective study, the concentrations of CA 125, 17 beta-oestradiol and progesterone were assayed in 52 consecutive ovarian cysts, laparoscopically suspected to be endometriomas. Cysts with dark brown 'chocolate' fluid (n = 42) were excised by CO2-laser endoscopy. Cysts with clear fluid were diagnosed by pathology as follicular cysts (n = 5) or pseudoperitoneal cysts (n = 5). Fluids (n = 53) aspirated during echo-guided puncture for in-vitro fertilization (IVF) were assayed simultaneously. Of the 42 women undergoing a cystectomy, the clinical diagnosis of an endometrioma was confirmed by pathology in only 68%, the other cases being corpora lutea (27%) or follicular cysts (5%). Cyst fluids from corpora lutea had lower CA 125 concentrations (< 1000 IU/ml) together with high 17 beta-oestradiol concentrations (> 2000 pg/ml) and/or high progesterone concentrations (> 100 ng/ml). Endometriotic cysts had either very high CA 125 concentrations (> 10,000 IU/ml) as occurred in 78% or lower CA 125 concentrations (< 1000 IU/ml) together with low 17 beta-oestradiol and/or progesterone concentrations. 'Chocolate' fluid-containing cysts aspirated during IVF had similar concentration profiles of CA 125, 17 beta-oestradiol and progesterone and the diagnoses derived from these concentrations were not contradicted in 19/27 women undergoing a laparoscopy within 4 months. In eight women, however, with high CA 125 concentrations in their cyst fluid, no endometriotic cysts were found at laparoscopy. Only 68% of cysts containing 'chocolate' material were endometriotic cysts and CA 125 could be useful in making this diagnosis. This method is recommended when dark brown fluid is aspirated in IVF.