Hormone therapy (also called endocrine therapy) is a treatment for cancers that depend on hormones to grow, mainly hormone receptor-positive breast cancer and prostate cancer. The idea is simple: if cancer cells rely on hormones for fuel, cut off that supply line — either by stopping the body from making the hormone or by blocking the hormone receptors on the cancer cells.
Hormone therapy is usually taken as a pill or given as a regular injection, and it does not require hospitalization. Side effects are generally milder than those of chemotherapy. It is a classic example of slow and steady wins the race in cancer treatment: breast cancer patients may take it for five to ten years, while prostate cancer patients may use it long term.
How It Works
Breast cancer: About 70% of breast cancers have estrogen receptors on the surface of their cells (ER-positive), and estrogen binding to these receptors stimulates cancer cell growth. Hormone therapy takes one of two approaches — using a drug such as tamoxifen to occupy the receptors so estrogen cannot take effect, or using a drug such as an aromatase inhibitor to reduce the body's production of estrogen.
Prostate cancer: Cancer cells depend on androgens (mainly testosterone) to grow. Androgen deprivation therapy (ADT) uses injections to suppress testosterone production by the testes, or oral drugs to block the androgen receptor, cutting off the cancer cells' fuel supply. Newer-generation oral drugs such as abiraterone and enzalutamide can block androgen signaling more completely.
When It Is Used
Breast cancer: For patients with hormone receptor-positive disease (ER/PR-positive), adjuvant hormone therapy after surgery is standard and greatly reduces the risk of recurrence. For advanced hormone-positive breast cancer, hormone drugs (often combined with CDK4/6 inhibitors) are the first choice and are often more effective and better tolerated than chemotherapy. Premenopausal women may also need ovarian function suppression.
Prostate cancer: ADT is the cornerstone of treatment for metastatic prostate cancer, often combined with newer-generation hormone drugs or chemotherapy for greater effect. For locally advanced disease, hormone therapy is also used alongside radiation to improve the cure rate. Whether it applies depends on ER/PR testing for breast cancer, while for prostate cancer it is the starting point for almost all metastatic cases.
Common Side Effects and How to Manage Them
The side effects of hormone therapy come from lower hormone levels, and patients of both sexes may experience something like menopause: hot flashes, sweating, fatigue, mood swings, and reduced sex drive. For breast cancer drugs, tamoxifen requires attention to the risk of blood clots and endometrial problems (with regular gynecological check-ups), while aromatase inhibitors are more likely to cause joint pain and bone loss.
Side effects of ADT for prostate cancer include hot flashes, weight gain, muscle loss, osteoporosis, and metabolic changes. In either case, weight-bearing exercise (such as walking and resistance training), calcium and vitamin D supplementation, and regular bone density monitoring are all evidence-based ways to protect yourself. If side effects are bothering you, tell your doctor — there are alternative drugs and ways to relieve them, so do not quietly stop taking your medication.
Living Well During Treatment
Hormone therapy is a long-term battle, and sticking with it is the key to success: studies show that stopping breast cancer hormone therapy on your own increases the risk of recurrence. Fitting medication into your daily routine (such as taking it regularly after breakfast) and using a pill organizer or phone reminders are simple and effective strategies.
In daily life, regular exercise tackles hot flashes, weight, and bone problems all at once. Staying socially connected and having psychological support also matter. Remember, while you are on hormone therapy, you are still actively treating your cancer — that one pill a day is a daily victory.
Clinical Trials: One More Treatment Option
Hormone therapy keeps evolving: new oral SERDs, new combinations with CDK4/6 inhibitors, and earlier use of newer-generation hormone drugs in prostate cancer are all being tested in clinical trials.
The CancerLink platform can match you to breast and prostate cancer clinical studies currently recruiting in Hong Kong based on cancer type, stage, and genetic mutations. Once successfully matched and enrolled, study-related treatment costs are fully covered. After hormone therapy stops working, clinical trials are especially worth considering.
Hormone therapy may stay with you for years. Think of it as a long-term ally rather than a burden. If you have side effects, speak up; if you have questions, ask until you understand — by sticking with treatment, you are quietly and powerfully lowering your risk of recurrence.