Levonorgestrel Intrauterine System and Its Implications for Breast Cancer Risk: Systematic Review

Abstract

Introduction: Hormonal contraceptives, particularly the levonorgestrel-releasing intrauterine system (LNG-IUS), are widely used for contraception and treatment of various gynecological conditions. This systematic review aims to synthesize existing evidence on the risk of breast cancer and other malignancies associated with LNG-IUS use and other hormone therapies to provide a clearer understanding of their safety profiles. Method: This systematic review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Result: Five studies conducted in Norway, Finland, Sweden, and Israel were included. These studies employed both prospective and retrospective cohort designs, as well as case-control approaches, with sample sizes ranging from 2,015 to over 1.5 million women.  Conclusion: The studies reviewed indicate variability in breast cancer risk related to LNG-IUS use. While some suggest a potential increase in risk, particularly with long-term use or in younger women, others do not observe a significant association. The findings underline the need for individualized patient assessment and further research to clarify long-term cancer risks associated with LNG-IUS and other hormonal therapies.