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.