From the Guidelines
Hormonal IUDs may slightly increase breast cancer risk, but the overall risk remains very low for most women. Studies suggest a small increased relative risk (about 1.2-1.3 times) compared to women not using hormonal contraception, which translates to a very small absolute risk increase 1. The levonorgestrel-releasing IUDs (brand names include Mirena, Kyleena, Liletta, and Skyla) work primarily by releasing small amounts of progestin locally in the uterus, with minimal systemic hormone absorption compared to other hormonal contraceptives. This risk appears to be temporary and diminishes after the IUD is removed. For context, many other factors influence breast cancer risk more significantly, including age, family history, and lifestyle factors. Women with a strong family history of breast cancer or known genetic mutations (like BRCA1/2) should discuss their specific risk profile with their healthcare provider. The benefits of hormonal IUDs, including highly effective contraception, reduced menstrual bleeding, and treatment of conditions like endometriosis, often outweigh this small risk for most women. Regular breast cancer screening according to age-appropriate guidelines remains important for all women regardless of contraceptive choice.
Key Considerations
- The risk of breast cancer associated with hormonal IUDs is small and temporary 1.
- Other factors, such as age, family history, and lifestyle, have a greater impact on breast cancer risk.
- The benefits of hormonal IUDs, including effective contraception and reduced menstrual bleeding, often outweigh the small risk of breast cancer.
- Women with a strong family history of breast cancer or known genetic mutations should discuss their specific risk profile with their healthcare provider.
Recommendations
- Hormonal IUDs are a safe and effective contraceptive option for most women, including those with a history of breast cancer, except for those with current breast cancer, for whom the levonorgestrel IUD is category 4 1.
- Women should discuss their individual risk profile and contraceptive options with their healthcare provider.
- Regular breast cancer screening according to age-appropriate guidelines is essential for all women, regardless of contraceptive choice.
From the Research
Relationship Between Hormonal IUD and Breast Cancer Risk
- The use of a levonorgestrel-releasing intrauterine device (LNG-IUD) has been associated with a 13% higher risk of breast cancer, as found in a national cohort study in Sweden 2.
- However, another study found no increased risk of breast cancer for users of LNG-IUD, with relative risk estimates approaching unity and 95% CI crossing 1.0 for all comparisons 3.
- A review of available literature suggests that there is no conclusive evidence to determine whether the use of LNG-IUD increases the risk of breast cancer, with one study considered "C" level finding no such increase 4.
- The risk of breast cancer diagnosis with exposure to hormonal contraception, including LNG-IUD, is considered very small and outweighed by its contraceptive benefits, but there are still outstanding questions due to the paucity of available evidence 5.
Considerations for Clinical Practice
- Clinical recommendations regarding the use of LNG-IUD should carefully weigh its potential benefits and risks, particularly for women with a family history of breast cancer 2.
- Close monitoring is advisable for the potential development of breast cancer, particularly among women with a family history of breast cancer 2.
- The use of LNG-IUD in women with a personal history of breast cancer should be approached with caution, and its use should be considered only after a multidisciplinary collective formal decision and with a regular medical follow-up 4.
- LNG-IUD placement in a young patient with a personal history of breast cancer on tamoxifen and a bicornuate uterus is considered a safe and feasible alternative for contraception 6.