The study with that finding, “Efficacy of levonorgestrel releasing intrauterine system as a postoperative maintenance therapy of endometriosis: A meta-analysis,” was published by the European Journal of Obstetrics & Gynecology and Reproductive Biology.
Endometriosis is gynecological disease characterized mostly by chronic pain, resulting in recurrent pelvic pain, painful periods, and painful sexual intercourse.
Some hormone-based treatment strategies have shown potential to help manage endometriosis symptoms, but no fully effective pharmacological treatment is yet available. The only solution for most of these women is to remove the endometrium lesions by surgery. However, 21.5% experience disease recurrence within two years after surgery, and this rate increases up to about 50% at five years after surgery.
These numbers highlight the emergent need for effective maintenance treatment strategies that can protect women in the long run.
Oral contraceptives and gonadotropin-releasing hormone (GnRH) analogues have been suggested as potential post-operative treatments. But those often have been reported to cause undesired side effects or to have a short-term therapeutic activity.
Another potential strategy is the use of Mirena, an intrauterine device that contains a synthetic hormone called levonorgestrel. This hormone is very gradually released inside the uterus over a five-year period, which has been shown to reduce endometriosis-associated pain while causing very few systemic (body-wide) effects.
Korean researchers compared the potential of these different treatment strategies by reviewing available information. They analyzed clinical data collected from 491 women with endometriosis who had been documented in four randomized controlled trials, one prospective and two retrospective studies.
When compared to expectant management (no treatment after surgical treatment), Mirena significantly reduced the incidence of painful periods and non-cyclic pelvic pain. It also reduced by 70% the chances of recurring painful periods, but it did not significantly protect the patients from endometric lesion re-appearance.
Oral contraceptives were found to have an enhanced pain-reducing effect compared to Mirena. Still, the effectiveness to protect women from recurring endometriosis symptoms was similar with both treatments. Despite these findings, more patients treated with Mirena reported being significantly more satisfied with the overall treatment outcome, than those treated with oral contraceptives.
After analysis of data on the use of GnRH analogues, researchers found that the two therapies had similar potential to reduce endometriosis-associated pain. Still, Mirena use was associated with a 27-times increased risk of irregular vaginal bleeding than GnRH analogues.
Finally, Mirena also more effectively reduced pain compared to Danocrine (danazol) treatment, with 68% of the patients reporting being satisfied with the overall outcome of Mirena treatment.
Collectively, these findings demonstrated that Mirena had “a significant effect on preventing the recurrence” of painful periods, without occurrence of systemic adverse reactions reported with other treatment strategies.
“Therefore, [Mirena] might be a treatment option as a maintenance therapy after surgical management for endometriosis,” researchers stated.
Additional studies are still warranted to compare the potential of dienogest, a fourth-generation selective progestin, to Mirena as post-operative maintenance therapy for endometriosis.