Hormone Therapy in Breast Cancer

Introduction to Hormone Therapy

Hormone therapy is used in breast cancer patients with hormone receptor-positive tumors to improve progression-free survival and overall survival by blocking the stimulatory effects of estrogen on cancer cells, as recommended by the American Society of Clinical Oncology 1, 2

Hormone therapy targets estrogen-dependent tumor growth in hormone receptor-positive breast cancers, and treatment works by either blocking estrogen receptors or suppressing ovarian function in premenopausal women, or reducing estrogen production in postmenopausal women, with a strength of evidence level I 3, 4

For premenopausal women, tamoxifen with ovarian ablation is the standard approach, according to the European Society for Medical Oncology 3
For postmenopausal women, aromatase inhibitors are superior to tamoxifen in first-line therapy, as stated by the National Comprehensive Cancer Network 2, 3

In the adjuvant setting, standard tamoxifen treatment is 5 years at 20 mg daily, as recommended by the British Cancer Society 4
In the metastatic setting, endocrine therapy should be the initial treatment for patients with hormone receptor-positive metastatic breast cancer, except in cases of immediately life-threatening disease, according to the American Society of Clinical Oncology 1, 5

Hormone receptor status of the tumor is a key factor in treatment selection, and hormone therapy should only be used in receptor-positive tumors, as recommended by the European Society for Medical Oncology 2, 4
Menopausal status, prior hormone therapy exposure, and disease-free interval are also important factors in treatment selection, as stated by the National Comprehensive Cancer Network 2, 3

Hormone therapy should not be prescribed to women with tumors that do not express estrogen receptors, according to the British Cancer Society 4
Combined chemo-endocrine therapy is not recommended in the metastatic setting, as stated by the American Society of Clinical Oncology 3, 5
Regular gynecological examinations are recommended for patients on tamoxifen due to increased risk of endometrial cancer, as recommended by the European Society for Medical Oncology 4