Evaluating CA125 and VAS pain modifications following GnRH analog to exclude superficial endometriosis as cause of chronic pelvic pain

Background: The study aim was to assess the reliability in the diagnosis of superficial endometriosis of the combined evaluation of 2 parameters: modifications of serum CA125 and VAS pain score following 1 dose of GnRH analog (GnRH-a). Methods: Women with chronic pelvic pain (CPP) were managed by GnRH-a administration and diagnostic laparoscopy. Serum CA125 and VAS pain score were assessed for each patient at the early follicular phase and 2 months after the administration of 11.25 mg GnRH-a. Following laparoscopy, subjects were grouped into groups A (72 women with endometriosis) and B (46 women without endometriosis). A multivariate model for CA125 and VAS reduction and for the combination of the 2 markers was calculated using logistic regression and diagnostic performance was evaluated as the AUC of ROC curve. Main outcome measure was the accuracy of the modifications of serum CA125 levels and VAS score following GnRH-a, in patients with histological diagnosis of superficial endometriosis. Results: At baseline, both groups showed similar CA125 levels and VAS scores. Two months after GnRH-a, a significant reduction (delta [Δ]) in CA125 levels and VAS pain score was observed in group A only. AUCs for ΔCA125, ΔVAS score and for combination of these 2 deltas were 0.90, 0.83 and 0.97, respectively. Conclusions: The assessment of serum CA125 and VAS pain score following GnRH-a demonstrates good reliability to exclude superficial endometriosis in patients with CPP. The response to GnRH-a administration in these women could therefore be employed as an ex juvantibus criterion for endometriosis diagnosis. © 2015 Wichtig Publishing.