CA 125 Modifications Throughout Menstrual Cycle and following GnRH-Analog Administration to Diagnose Endometriosis as Cause of Chronic Pelvic Pain. A Prospective Controlled Study

Abstract

Purpose Endometriosis is the leading single cause of chronic pelvic pain (CPP). To date, the gold standard to diagnose this condition is histologic confirmation of lesions obtained by surgery. However, a noninvasive and cheaper tool for early diagnosis is strongly needed. The aim of this study is twofold: first, to assess the diagnostic accuracy to detect endometriosis of serum CA 125 modifications throughout the menstrual cycle, and second, to analyze whether variations in CA 125 levels following one dose of GnRH-analog (GnRH-a) may increase the diagnostic value of the assay. Methods 84 women scheduled for a diagnostic laparoscopy for CPP (group A) and another 12 women scheduled for diagnostic laparoscopy for unexplained infertility (group B) were enrolled as cases and controls. Serum CA125 was determined for each patient at the early follicular and luteal phases. Prior to surgery, patients from group A received one vial of leuprolide acetate depot. Following laparoscopy and histologic examination, cases were sub-grouped into group A1 (subjects with endometriosis) and group A2 (subjects without endometriosis). Results Plasma CA125 levels during the early follicular phase were significantly higher than those recorded in the luteal phase in all groups and they were significantly higher in group A1 in comparison with groups A2 and B. One month after GnRH administration, a significant reduction in plasma CA-125 levels was only observed in group A1. Conclusions The assessment of serum CA 125 modifications throughout the menstrual cycle and following one dose of GnRH-a demonstrated good diagnostic accuracy to detect endometriosis in patients with CPP. Women with endometriosis are characterized by a significant increase in CA125 levels during the early follicular phase and by a significant decrease following GnRH-a administration.