Long-term efficacy and safety of levonorgestrel releasing intrauterine system in the treatment of adenomyosis: evidence mapping

Purpose To summarize evidence on levonorgestrel releasing intrauterine system (LNG-IUS) in the treatment of adenomyosis (AM) and to identify potential research gaps. Methods Search was conducted in MEDLINE, The Cochrane Library, EMBASE, CBM, CNKI, and Wanfang. We included studies investigating patients with AM treated with LNG-IUS combined with conservative therapy. Results Thirty-nine studies compared LNG-IUS with other conservative therapeutic drugs. The most common comparison was GnRH-a + LNG-IUS vs. LNG-IUS alone, followed by LNG-IUS vs. mifepristone, expected treatment, and GnRH-a. GnRH-a + LNG-IUS was more beneficial in reducing the intensity of dysmenorrhea than LNG-IUS alone at the 6-month follow-up in patients with an enlarged uterus and moderate to severe dysmenorrhea. Large and well-designed studies are needed to confirm the efficacy of LNG-IUS and GnRH-a on reducing uterine volume at 6-month follow-up. Thirty-two studies investigated LNG-IUS as the postoperative management. The most common comparison was surgical excision + LNG-IUS vs. surgical excision. Results showed VAS scores were lower in the surgical excision + LNG-IUS group than in the surgical excision group at the 1-year follow-up. Evidence on endometrial thickness, quality of life, adverse events and beneficial effect at 3 and 5 years are needed. Conclusions Combined GnRH-a and LNG-IUS treatment was more efficacious than LNG-IUS alone for patients with an enlarged uterus and moderate to severe dysmenorrhea. Moreover, LNG-IUS seemed to show potential long-term benefits in postoperative therapy, warranting further meta-analysis for confirmation.