The effectiveness of a levonorgestrel-releasing intrauterine system (LNG-IUS) in the treatment of endometrial hyperplasia--a long-term follow-up study.

Objectives: Medical treatment of non-atypical endometrial hyperplasia with oral progestogens has limited efficacy and poor compliance. A levonorgestrel-releasing intrauterine system (LNG-IUS) has been shown to successfully treat hyperplasia in small-sized studies. Our aim was to examine the effectiveness of LNG-IUS in a larger study with long-term follow up.

Study Design: Prospective observational study of 105 women diagnosed with endometrial hyperplasia and treated with LNG-IUS between 1999 and 2004 at a University Teaching hospital. Baseline characteristics and outpatient endometrial Pipelle sampling were undertaken at 3 and 6 months post LNG-IUS insertion and 6-monthly intervals thereafter in all cases. Outcome included histological data derived from both Pipelle and uterine histologies at 1 and 2 years LNG-IUS therapy.

Results: LNG-IUS achieved endometrial regression in 90% (94/105) of cases by 2 years, with a significant proportion (96%, 90/94) achieving this within 1 year. Regression occurred in 88/96 (92%) of non-atypical and 6/9 (67%) of atypical hyperplasias, and in all 22 cases of endometrial hyperplasia associated with HRT. Regression rates did not differ between histological types of hyperplasia. Twenty-three women (22%) underwent hysterectomy of which 13 were indicated and 10 were performed at patient request despite regressed endometrium. Two cases of cancer (one uterine and one ovarian) were identified.

Conclusion: LNG-IUS is highly effective in treating endometrial hyperplasia. Beneficial effects are observed by the majority within 1 year. Treatment can be reliably monitored through regular 6-montly outpatient endometrial Pipelle surveillance. LNG-IUS treatment of non-atypical hyperplasias is likely to reduce the number of hysterectomies performed in this subgroup.