Effect of a hormone-releasing intrauterine system (Mirena(®)) on aromatase and Cox-2 expression in patients with adenomyosis submitted or not, to endometrial resection.

OBJECTIVE: To investigate the effect of a levonorgestrel-releasing intrauterine system (Mirena(®)) on aromatase and cyclooxygenase-2 (Cox-2) expression in the endometrium of patients with adenomyosis who were submitted to endometrial resection at the time of insertion, compared to a group not submitted to endometrial resection and a group of controls with adenomyosis not submitted to any previous hormonal treatment.

PATIENTS AND METHODS: Patients with adenomyosis (n = 89) were included in this study. Twenty- two patients had been using Mirena(®) for 5 years but had not been submitted to endometrial resection prior to insertion of the device. Twenty-four patients were submitted to endometrial resection at the time of Mirena(®) insertion. The remaining 43 patients with adenomyosis had undergone no previous hormonal treatment and served as a control group. Cox-2 and aromatase expression were determined in the endometrium by immunohistochemistry.

RESULTS: Use of Mirena(®) for 5 years reduced aromatase expression in the endometrium; however, this reduction was significantly greater in the uteri previously submitted to endometrial resection. The reduction in Cox-2 expression was significant only in the uteri submitted to endometrial resection followed by the insertion of Mirena(®).

CONCLUSION: Endometrial resection followed by the insertion of Mirena(®) was associated with greater rates of amenorrhea in patients with adenomyosis, which in turn were associated with a more effective inhibition of aromatase and Cox-2 expression in the endometrium.