Testosterone Replacement Therapy in Females with History of Breast Cancer

Rationale and Evidence

The American Society of Clinical Oncology (ASCO) guidelines specifically recommend against testosterone/androgen supplementation in patients with breast cancer 1, 2, 3
Testosterone can be aromatized to estrogen, potentially stimulating hormone-sensitive breast cancer cells, which is a concern for patients with breast cancer 4, 5

Testosterone can be converted to estradiol by the aromatase enzyme present in breast tissue and adipose tissue, potentially stimulating estrogen receptor-positive breast cancer cells, leading to recurrence or progression 4, 6

For transgender and gender-diverse individuals with a history of breast cancer who are considering gender-affirming hormone therapy (GAHT), the decision is particularly complex, and some may choose to continue hormone therapy despite a cancer diagnosis due to the importance of gender-affirming care for their quality of life 7
A thorough discussion of the potential risks is essential, weighing the benefits of GAHT against the risk of cancer recurrence 7

Non-hormonal treatments should be considered first-line for females with a history of breast cancer experiencing symptoms that might otherwise be treated with testosterone, such as sexual dysfunction or decreased libido 8
Management of symptoms should follow similar approaches used for women without using testosterone 4
Consultation with both oncology and endocrinology specialists is recommended to develop a comprehensive management plan 7

Patients with a history of breast cancer should receive regular follow-up care with physicians experienced in cancer surveillance, including regular breast examinations and appropriate imaging studies according to standard breast cancer surveillance protocols 3
Patients should be counseled about symptoms of recurrence, including new lumps, bone pain, chest pain, dyspnea, abdominal pain, or persistent headaches 3