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Evidence summaries

Levonorgestrel Intrauterine System for Endometrial Protection in Women with Breast Cancer on Adjuvant Tamoxifen

Levonorgestrel intrauterine system (LNG-IUS) is effective for decreasing endometrial polyps and endometrial hyperplasia in women with breast cancer on adjuvant tamoxifen compared with no treatment, but at the cost of more bleeding and spotting in the first two years. Level of evidence: "A"

A Cochrane review [Abstract] 1 included 4 studies with a total of 543 subjects. The levonorgestrel-releasing intrauterine device LNG-IUS in tamoxifen users led to a significant reduction in the incidence of endometrial polyps (follow-up 12 months, Peto OR 0.22, 95% CI 0.08 to 0.64, 2studies, n=212, I²=0%) and over a long-term follow-up period (24 to 60 months) (Peto OR 0.22, 95% CI 0.13 to 0.39, 4 studies, n = 417) and endometrial hyperplasia 8 follow-up 24 to 60 months, Peto OR 0.13, 95% CI 0.03 to 0.67, 4 studies, n=417, I²=0%). Also the LNG-IUS led to a reduction in the incidence of endometrial hyperplasia over a long-term follow-up period (24 to 60 months) (Peto OR 0.13, 95% CI 0.03 to 0.67, four studies, n = 417, I² = 0%, moderate quality evidence). By 24 months of follow-up, abnormal vaginal bleeding or spotting occurred less frequently compared to 12 months of follow-up in the LNG-IUS treatment group but was still more common than the control group (Peto OR 7.26, 95% CI 3.37 to 15.66, 3 studies, n = 376, I² = 0%, moderate quality evidence). By 24 months of follow-up, abnormal vaginal bleeding or spotting occurred less frequently compared to 12 months of follow-up in the LNG-IUS treatment group but was still more common than the control group (Peto OR 2.72, 95% CI 1.04 to 7.10, 2 studies, n = 233, I² = 0%, moderate quality evidence). By 60 months of follow-up, no cases of abnormal vaginal bleeding or spotting were reported in either group. The numbers of events for the following outcomes were low: fibroids (n = 13), breast cancer recurrence (n = 18), and breast cancer-related deaths (n = 16).

    References

    • Romero SA, Young K, Hickey M et al. Levonorgestrel intrauterine system for endometrial protection in women with breast cancer on adjuvant tamoxifen. Cochrane Database Syst Rev 2020;(12):CD007245.[PubMed]

Primary/Secondary Keywords