The specificity of CA125 is reported to be higher than 80% in most studies. This high level of specificity is achieved in selected women with infertility or pain, who are known to be at risk for endometriosis. The low level of sensitivity of CA125 (20% to 50% in most studies) poses limitations for the clinical use of this test for diagnosis of endometriosis. Theoretically, the sensitivity might increase during the menstrual period, when the increase in CA125 level is more pronounced in women who have endometriosis. Studies using cutoff levels of 35 U/mL or 85 U/mL did not find a significant improvement in sensitivity (221,222,224). A sensitivity of 66% was found when the CA125 level was determined during both the follicular phase and the menstrual phase in each patient and when the ratio of menstrual versus follicular values (>1.5) was used instead of one CA125 level (222). Other studies reported that the value of CA125 in diagnosis of endometriosis is limited but higher for moderate to severe disease, especially if serum CA125 concentrations are measured during the midfollicular phase (223,225).
Serial CA125 determinations may be useful to predict the recurrence of endometriosis after therapy (226,227). CA125 levels decrease after combined medical and surgical therapy or during medical treatment of endometriosis with danazol, gonadotropin-releasing hormone (GnRH) analogues, or gestrinone, but not with medroxyprogesterone acetate (MPA) or placebo (228–230). Levels of CA125 are reported to increase to pretreatment levels as early as 3, 4, or 6 months after the cessation of therapy with danazol, GnRH analogues, or gestrinone (218,229– 233). Posttreatment increases in CA125 levels are reported to correlate with endometriosis recurrence (217,227,234). Other studies did not substantiate a correlation between posttreatment CA125 levels and disease recurrence (228,231,235).
Laparoscopic Findings The laparoscopic findings of endometriosis include peritoneal lesions, ovarian endometriotic cysts, and deeply infiltrative endometriosis invading the peritoneal surface with a depth of at least 5 mm. Most patients with ovarian endometriotic cysts or deeply infiltrative endometriosis also have peritoneal disease.
Characteristic findings include typical (“powder-burn” or “gunshot”) lesions on the serosal surfaces of the peritoneum. These lesions are black, dark brown, or bluish nodules or small cysts containing old hemorrhage surrounded by a variable degree of fibrosis (Fig. 17.2). Endometriosis can appear as subtle lesions, including red implants (petechial, vesicular, polypoid, hemorrhagic, red ﬂamelike), serous or clear vesicles, white plaques or scarring, yellow-brown discoloration of the peritoneum, and subovarian adhesions (Fig. 17.3) (138,139,141,240,241). Histologic confirmation of the laparoscopic impression is essential for the diagnosis of endometriosis, for subtle lesions, and for the typical lesions reported to be histologically negative in 24% of cases (242,243).