Hormone therapy is an important treatment option for certain types of breast cancer, particularly cancers that use estrogen or progesterone to grow. Also called endocrine therapy, this approach reduces hormone production or blocks hormones from acting on cancer cells. Treatment may be recommended after surgery to lower the risk of recurrence, or it may be used for advanced breast cancer.
Hormone therapy for breast cancer is primarily used for hormone receptor positive cancers, which contain receptors that respond to estrogen or progesterone. These receptors can allow hormones to stimulate cancer cell growth. By reducing hormone levels or interfering with hormone receptors, treatment can slow or stop the growth of some cancer cells. Hormone therapy differs from hormone replacement therapy, which is used to manage certain symptoms associated with menopause. Breast cancer endocrine treatment is selected according to the disease stage, receptor status, treatment goals, and the patient's overall medical circumstances.
Hormone therapy targets the hormonal signals that support the growth of hormone receptor positive breast cancer. Before treatment begins, laboratory testing of tumor tissue usually determines whether the cancer expresses estrogen receptors, progesterone receptors, or both. Hormone receptor status helps doctors assess whether endocrine treatment is likely to be beneficial.
Several types of hormone therapy are available, and each works differently. The choice depends partly on whether a patient has reached menopause and whether the cancer is newly diagnosed, has returned, or has spread to other parts of the body.
Common treatment approaches include:
Tamoxifen: Blocks estrogen receptors in breast tissue, reducing estrogen's ability to stimulate cancer cell growth. It can be used in premenopausal and postmenopausal patients in appropriate circumstances.
Aromatase inhibitors: Medications such as anastrozole, letrozole, and exemestane reduce estrogen production. They are commonly used after menopause and may also be used before menopause with ovarian function suppression.
Ovarian function suppression: Medicines or procedures reduce ovarian hormone production in selected premenopausal patients. This approach may be combined with other endocrine treatments.
Fulvestrant: A selective estrogen receptor degrader that binds to estrogen receptors and promotes their breakdown. It is used in certain settings, particularly advanced hormone receptor positive breast cancer.
Other targeted combinations: For some advanced cancers, hormone therapy may be combined with targeted medicines, depending on tumor characteristics and previous treatment.
Hormone therapy may be recommended following surgery, sometimes alongside other treatments, to reduce the likelihood of breast cancer returning. It can also help control hormone receptor positive cancer that has spread or become recurrent. The expected benefits vary according to the cancer's biological features, stage, and individual risk factors.
Treatment duration depends on the clinical situation. For many people with early-stage hormone receptor positive breast cancer, endocrine therapy is prescribed for at least five years, with longer treatment considered for some patients. Regular medical appointments help assess treatment effectiveness, side effects, and whether adjustments are necessary.
Important considerations include:
Common side effects: Hot flashes, night sweats, fatigue, vaginal dryness, and changes in sexual health may occur, depending on the medication.
Bone health: Aromatase inhibitors and ovarian suppression can reduce bone density. Clinicians may recommend bone density assessments and appropriate preventive measures.
Medication-specific risks: Tamoxifen can increase the risk of blood clots and, in people with a uterus, endometrial cancer. Unusual bleeding or symptoms of a blood clot require prompt medical assessment.
Monitoring and adherence: Regular follow-up allows healthcare professionals to evaluate side effects and discuss strategies to help patients continue treatment safely.
Individualized decisions: Age, menopausal status, other medical conditions, recurrence risk, and personal preferences influence treatment selection.
Patients should discuss new symptoms, difficulties taking medication, and concerns about treatment duration with their oncology team rather than stopping prescribed therapy independently. The most suitable approach balances the expected benefits of cancer control with potential risks and effects on quality of life.
Hormone therapy remains an established component of treatment for hormone receptor positive breast cancer. Understanding the available medications, their possible benefits, and their limitations can help patients make informed decisions in partnership with their healthcare professionals. Individual treatment recommendations should be based on tumor testing, medical history, and current clinical guidance.