Anastrozole and levonorgrestrel-releasing intrauterine device in the treatment of endometriosis: a randomized clinical trial

Background To study the effectiveness of an aromatase inhibitor (Anastrozole) associated with levonorgestrel-releasing intrauterine device (LNG-IUD, Mirena (R)) in the treatment of endometriosis. Methods Prospective, randomized clinical trial. Setting: University Hospital (single center). Elegibility criteria: Endometriomas > 3 x 4 cm, CA-125 > 35 U/mL and endometriosis symptoms. Patients: Thirty-one women randomized to anastrozole + Mirena (R) + Conservative Surgery(CS) (n = 8), anastrozole + Mirena (R) + transvaginal ultrasound-guided puncture-aspiration (TUGPA) (n = 7), Mirena (R) + CS (n = 9), or Mirena (R) + TUGPA (n = 7). Interventions: Anastrozole 1 mg/day and/or only Mirena (R) for 6 months; CS (ovarian and fertility-sparing) or TUGPA of endometriomas one month after starting medical treatment. Main Outcome Measures: Visual analogic scale for symptoms, CA-125 levels, ultrasound findings of endometriomas and recurrences. Results A significant improvement in symptoms during the treatment (difference of 43%, 95% CI 29.9-56.2) occurred, which was maintained at 1 and 2 years. It was more significant in patients including anastrozole in their treatment (51%, 95% CI 33.3-68.7). For CA-125, the most significant decrease was observed in patients not taking anastrozole (73.8%, 95% CI 64.2-83.4 vs. 53.8%, 95% CI 25.7-81.6 under Mirena (R) + anastrozole). After CS for endometriosis, a reduction of ultrasound findings of endometriomas and long-term recurrence occurred, with or without anastrozole. At 4.2 +/- 1.7 years (95% CI 3.57-4.85), 88% of the patients who underwent CS were asymptomatic, without medication or reoperation, compared to only 21% if TUGPA was performed, with or without anastrozole (p = 0.019). Conclusions Dosing anastrozole for 6 months, starting one month before CS of endometriosis, reduces significantly the painful symptoms and delays recurrence, but has no other significant advantages over the single insertion of LNG-IUD (Mirena (R)) during the same time. Anastrozole and/or only Mirena (R) associated with TUGPA are not effective.

Automated summary

The study found that combination therapy with an aromatase inhibitor and levonorgestrel-releasing intrauterine device led to significant improvement in symptoms of endometriosis, but had mixed effects on CA-125 levels. Surgical treatment significantly reduced ultrasound findings and long-term recurrence of endometriomas.