Effects of the levonorgestrel-releasing intrauterine system and a gonadotrophin releasing hormone agonist in the symptomatic treatment of minimal to moderate endometriosis

Endometriosis is a chronic inflammatory disease that responds to steroidal manipulation. The gonadotrophin-releasing hormone (GnRH) agonist is the gold standard for the treatment of endometriosis. The levonorgestrel-relasing intrauterine system (LNG-IUS) has been shown in small pilot studies to be an acceptable and effective symptomatic treatment option. The studies in this thesis were in two parts. The first was investigating the mechanisms by which the LNG-IUS was effective in the symptomatic treatment of endometriosis. The symptoms were improved by significant down regulation of estrogen (ER) and progesterone (PR) receptors as well as the reduction in mast cells number present in the ectopic endometrium (P<0.05). The second was a comparative randomized study comparing the efficacy of the LNG-IUS and the GnRH agonist. This was via the ER and PR and the clinical outcome of the patients. The ER and PR were down-regulated by the GnRH agonist (P<0.05) in the ectopic endometrium while the ER, PR-A and the stromal compartment of PR-B were down-regulated (P<0.05) by the LNG-IUS. These were also improvement in the clinical symptoms as seen in the visual analogue scale (VAS) score in both treatment groups (P<0.05). When the concentration levels of Interleukin-6 (IL-6) and Soluble Intracellular Adhesion molecule-I (sICAM-I) in the peritoneal fluid (PF) were compared before and after treatment with the LNG-IUS and the GnRH agonist there was significance difference in IL-6 levels (P<0.05) with the LNG-IUS but not with the GnRH agonist and no differences in the sICAM-1 levels with the use of either medication. In conclusion the LNG-IUS improves symptoms of endometriosis via the down regulation of ER, PR and reduction in mast cells number. The efficacy of the LNG-IUS was comparable to that of the GnRH agonist as evidence by the patients‘ clinical outcome and their effects on ER and PR.