From the Guidelines
Myfembree (relugolix, estradiol, and norethindrone acetate) has not been shown to increase the risk of breast cancer, based on the most recent and highest quality evidence available. This medication is primarily used to manage heavy menstrual bleeding associated with uterine fibroids and for moderate to severe pain associated with endometriosis. The estrogen component in Myfembree is lower than in many traditional hormone therapies, which may contribute to its favorable safety profile regarding breast cancer risk 1. However, Myfembree is contraindicated in women with a history of breast cancer or other estrogen-dependent neoplasms because the estrogen component could potentially stimulate growth of existing hormone-sensitive cancer cells.
For women with a strong family history of breast cancer or personal risk factors, healthcare providers should conduct a thorough risk assessment before prescribing Myfembree, considering factors such as increasing patient age, family history of breast cancer at a young age, early menarche, late menopause, nulliparity, and older age at first live childbirth 1. Regular breast examinations and mammograms according to age-appropriate screening guidelines remain important while taking this medication. The medication works by suppressing ovarian function through relugolix (a GnRH antagonist) while providing hormone replacement with estradiol and norethindrone to prevent bone loss and manage symptoms associated with low estrogen levels.
Some key points to consider when evaluating the risk of breast cancer associated with Myfembree include:
- The medication's estrogen component is lower than in many traditional hormone therapies
- Myfembree is contraindicated in women with a history of breast cancer or other estrogen-dependent neoplasms
- Women with a strong family history of breast cancer or personal risk factors should undergo thorough risk assessment before prescribing Myfembree
- Regular breast examinations and mammograms are important while taking this medication
- A healthy lifestyle, including a balanced diet and regular physical activity, can help reduce the risk of breast cancer, as suggested by the American Cancer Society guidelines on nutrition and physical activity for cancer prevention 1.
From the Research
Risk of Breast Cancer Associated with Myfembree (Relugolix)
- The risk of breast cancer associated with Myfembree (relugolix) is not directly addressed in the provided studies 2, 3, 4, 5, 6.
- However, studies discuss the risk of breast cancer associated with hormone replacement therapy (HRT) and other factors 2, 5.
- One study notes that short-term exposure to HRT for symptom relief may exceed its potential harms, including the associated increased risk of breast cancer diagnosis, although the degree of risk conferred appears equivalent to, or less than that of, other lifestyle risk factors for this condition 2.
- Another study models the risks associated with menopausal hormone therapy (MHT) use in women with varying breast cancer family histories, but does not specifically address Myfembree (relugolix) 5.
- A study on breast cancer prevention in high-risk women discusses the use of selective oestrogen receptor modulators (SERMs) and aromatase inhibitors (AIs) to reduce breast cancer risk, but does not mention Myfembree (relugolix) 6.
- The study on Myfembree (relugolix) is focused on its use in treating uterine fibroids, and does not address the risk of breast cancer 3.