Hormone Therapy for Cancer
Some cancers use the body's hormones, such as estrogen or testosterone, as fuel. Hormone therapy (also called endocrine therapy) slows or stops these cancers by lowering hormone levels or blocking hormones from reaching cancer cells. It is a main treatment for hormone receptor-positive breast cancer and for prostate cancer, and it is used for some other cancers too. This guide explains the types of hormone therapy, how long it lasts, common side effects and how to manage them, and questions to ask your care team.
How Hormone Therapy Works
Hormones are chemical messengers. Some cancer cells have receptors (docking sites) for hormones. When a hormone attaches, it tells the cell to grow and divide. Hormone therapy interrupts this in one of three ways:
- Stopping the body from making the hormone. Examples: aromatase inhibitors lower estrogen after menopause; LHRH (GnRH) drugs switch off the ovaries or testicles; surgery removes them.
- Blocking the receptor. Examples: tamoxifen blocks estrogen receptors; bicalutamide and enzalutamide block androgen receptors.
- Destroying the receptor. Example: fulvestrant and newer oral drugs called SERDs break down the estrogen receptor.
Hormone therapy does not usually kill cancer cells right away like chemotherapy does. It starves them of growth signals. That is why it is often given for years, to keep any remaining cancer cells from growing.
Hormone therapy is not HRT
Menopausal hormone replacement therapy (HRT) gives estrogen and sometimes progesterone to relieve menopause symptoms. Cancer hormone therapy does the opposite: it lowers or blocks hormones. In fact, HRT is usually avoided in people with hormone receptor-positive breast cancer.
Who Gets Hormone Therapy
Hormone therapy only works if the cancer depends on hormones. Doctors find this out with tests on the tumor tissue.
- Breast cancer: Every invasive breast cancer is tested for estrogen receptors (ER) and progesterone receptors (PR). About 2 out of 3 breast cancers are hormone receptor-positive. If ER is positive (1% or more of cells stain), hormone therapy is usually recommended. Cancers with only 1% to 10% ER staining ("ER-low") may benefit less.
- Prostate cancer: Almost all prostate cancers depend on androgens (male hormones such as testosterone) at first, so no receptor test is needed.
- Endometrial, ovarian and other cancers: Receptor testing may help decide whether hormone therapy is an option.
When it is used
- Adjuvant (after surgery): to lower the chance the cancer returns
- Neoadjuvant (before surgery): to shrink a tumor first, sometimes used in older women with breast cancer
- With radiation: for many men with intermediate- or high-risk prostate cancer
- Advanced or metastatic cancer: to control the cancer, often for years
- Risk reduction: to lower the chance of breast cancer in people at high risk
Hormone Therapy for Breast Cancer
For hormone receptor-positive breast cancer, hormone therapy is one of the most effective treatments available. After surgery, about 5 years of tamoxifen lowers the chance of the cancer coming back by roughly 40% and the risk of dying from breast cancer by about a third, and aromatase inhibitors lower recurrence further after menopause.
| Drug type | Examples | How it works | Used for |
|---|---|---|---|
| SERM (selective estrogen receptor modulator) | Tamoxifen; toremifene | Blocks estrogen receptors in breast tissue | Before or after menopause; men; DCIS; risk reduction |
| Aromatase inhibitors (AIs) | Letrozole, anastrozole, exemestane | Lower estrogen made outside the ovaries | After menopause, or before menopause with ovarian suppression |
| Ovarian suppression | Goserelin (Zoladex), leuprolide (Lupron), triptorelin; surgery to remove ovaries | Stops the ovaries making estrogen | Premenopausal women, combined with tamoxifen or an AI |
| SERDs (selective estrogen receptor degraders) | Fulvestrant (injection); elacestrant (Orserdu) and newer oral SERDs | Block and break down estrogen receptors | Advanced breast cancer; oral SERDs mainly for ESR1-mutated cancer |
Which drug is used?
- After menopause: An aromatase inhibitor is usually preferred because it lowers recurrence somewhat more than tamoxifen. Tamoxifen is a good alternative if AIs cause problems.
- Before menopause: Tamoxifen alone for lower-risk cancer. For higher-risk cancer, ovarian suppression plus tamoxifen or an aromatase inhibitor, based on the SOFT and TEXT trials.
- Men: Tamoxifen is the standard. If an AI is used, it is combined with a drug that lowers testosterone.
- Older women: Hormone therapy is often the most important treatment. See our section on letrozole in older women.
How long?
The standard is at least 5 years. Many people, especially those with larger tumors or cancer in lymph nodes, are offered a total of 7 to 10 years. Treatment may be tamoxifen alone, an AI alone, or a switch from one to the other. The right length balances the extra benefit against side effects, bone health and your preferences.
Advanced breast cancer
For hormone receptor-positive, HER2-negative breast cancer that has spread, hormone therapy combined with a targeted drug is usually the first treatment (see Combinations). When one hormone therapy stops working, another often can, before chemotherapy is needed.
Hormone Therapy for Prostate Cancer
Prostate cancer cells usually need androgens (testosterone) to grow. Lowering testosterone, called androgen deprivation therapy (ADT), is a backbone of treatment for advanced prostate cancer and is combined with radiation for many localized cancers.
| Type | Examples | How it works |
|---|---|---|
| LHRH (GnRH) agonists | Leuprolide (Lupron, Eligard), goserelin (Zoladex), triptorelin (Trelstar), histrelin implant | Injections or implant that switch off testosterone production. Can cause a short testosterone "flare" at first, so an antiandrogen may be given for a few weeks. |
| LHRH (GnRH) antagonists | Degarelix (Firmagon, monthly injection), relugolix (Orgovyx, daily pill) | Lower testosterone quickly without a flare |
| Orchiectomy | Surgical removal of the testicles | Permanent, one-time way to lower testosterone |
| Androgen receptor pathway inhibitors | Enzalutamide (Xtandi), apalutamide (Erleada), darolutamide (Nubeqa), abiraterone (Zytiga, with a steroid) | Block the androgen receptor or stop androgen production in the adrenal glands and tumor; usually added to ADT |
| Older antiandrogens | Bicalutamide, flutamide, nilutamide | Block androgen receptors; mainly used briefly to prevent flare |
How long?
- With radiation for localized cancer: often 4 to 6 months for intermediate risk, and 18 months to 3 years for high risk.
- Rising PSA after treatment or advanced cancer: often long term. Some men use intermittent ADT, with breaks when PSA is low.
- Metastatic cancer: ADT continues, usually with an added androgen receptor pathway inhibitor and sometimes chemotherapy.
Side effects specific to men
Hot flashes, lower sex drive and erectile dysfunction, fatigue, loss of muscle, weight gain around the middle, breast tenderness or growth, bone loss, mood changes, and a higher risk of diabetes and heart problems. Exercise, especially resistance training, helps many of these. Bone density checks and heart risk management are recommended for men on long-term ADT.
Other Cancers
- Endometrial (uterine) cancer: Progestins such as megestrol acetate or medroxyprogesterone, a progestin-releasing IUD for selected early cancers when preserving fertility, and aromatase inhibitors or tamoxifen for advanced disease.
- Ovarian cancer: Letrozole or other hormone therapy is used for some low-grade serous ovarian cancers and certain recurrent cancers.
- Thyroid cancer: After surgery, levothyroxine replaces thyroid hormone and, in some higher-risk cases, is dosed to keep TSH low, which may slow growth of remaining cancer cells.
- Neuroendocrine tumors: Somatostatin analogs (octreotide, lanreotide) control hormone-related symptoms and can slow tumor growth.
- Some breast cancer-related conditions, such as DCIS and atypical hyperplasia, may be treated with tamoxifen or an AI to lower future risk.
Combinations With Targeted Drugs
For advanced hormone receptor-positive, HER2-negative breast cancer, and for some high-risk early breast cancers, hormone therapy is combined with targeted therapy:
- CDK4/6 inhibitors: palbociclib (Ibrance), ribociclib (Kisqali), abemaciclib (Verzenio). Added to an aromatase inhibitor or fulvestrant, they roughly double the time before advanced cancer grows. Abemaciclib and ribociclib are also approved with hormone therapy for certain higher-risk early breast cancers.
- PI3K/AKT/mTOR pathway drugs: alpelisib, capivasertib, inavolisib, and everolimus (with exemestane) for cancers with certain gene changes or after earlier treatment.
- Oral SERDs: elacestrant and newer drugs for cancers with an ESR1 mutation, found with a blood or tissue test.
These combinations add side effects such as low white blood counts, diarrhea, high blood sugar or mouth sores, so they need closer monitoring than hormone therapy alone.
Side Effects and How to Manage Them
Side effects depend on which hormone is lowered or blocked. Most are similar to menopause (for estrogen-lowering drugs) or to low testosterone (for ADT). Many are manageable, and reporting them early gives the best chance of finding a fix.
| Side effect | Most linked with | What helps |
|---|---|---|
| Hot flashes and night sweats | All hormone therapies | Cooling strategies, venlafaxine, gabapentin, oxybutynin, CBT, hypnosis |
| Joint pain and stiffness | Aromatase inhibitors | Exercise, pain relievers, acupuncture, duloxetine, switching drugs |
| Bone loss, fractures | AIs, ovarian suppression, ADT; tamoxifen before menopause | DEXA scans, calcium and vitamin D, exercise, bisphosphonates or denosumab |
| Fatigue | All, especially ADT | Regular exercise, sleep habits, treat anemia, thyroid and mood problems |
| Vaginal dryness, pain with sex | AIs, ovarian suppression | Moisturizers, lubricants, pelvic floor therapy; discuss vaginal estrogen with oncologist |
| Low sex drive, erectile problems | ADT; all estrogen-lowering therapy | Counseling, erectile dysfunction treatments, open conversation with your team |
| Mood changes, depression | All | Tell your team; counseling, support groups, medicine if needed |
| Blood clots, uterine cancer | Tamoxifen | Report leg swelling, chest pain, or abnormal vaginal bleeding promptly |
| Weight gain, muscle loss, diabetes risk | ADT | Resistance and aerobic exercise, diet, regular blood sugar checks |
| Heart and cholesterol changes | AIs, ADT | Blood pressure, cholesterol and blood sugar checks; stop smoking |
| Sleep problems | All | Treat night sweats, sleep routines, CBT for insomnia |
| Memory or concentration changes | Reported with several | Usually mild; organization tools, exercise, tell your team |
When to seek help right away
- Call 911: chest pain, sudden shortness of breath, coughing up blood, sudden weakness or numbness on one side, trouble speaking, or sudden vision loss (possible clot, heart attack or stroke).
- Call your care team soon: swelling or pain in one leg; vaginal bleeding after menopause; new bone pain; a fall or possible fracture; severe low mood or thoughts of self-harm; yellow skin or eyes.
See when to call your doctor for more.
Staying on Treatment
Hormone therapy only works if it is taken. Studies of women with early breast cancer have found that a large share, in some studies up to about half, stop or miss many doses before 5 years, and that stopping early is linked to a higher risk of recurrence and death. Side effects, cost, and not fully understanding the benefit are common reasons.
- Know your benefit. Ask your oncologist how much hormone therapy lowers your personal risk.
- Report side effects early. There are treatments for most of them, and switching drugs often helps.
- Use routines. Pill boxes, phone reminders, and linking doses to a daily habit.
- Ask about breaks before stopping. A short supervised break can help sort out which symptoms come from the drug.
- Talk about cost. Most pills are generic and inexpensive, and help is available.
- Planning pregnancy? Talk to your oncologist; a planned pause has been studied in the POSITIVE trial.
Tests and Monitoring
- Bone density (DEXA) scans before and during treatment with AIs, ovarian suppression or ADT
- Vitamin D, cholesterol, blood sugar and blood pressure, especially with AIs and ADT
- Hormone levels: estradiol to confirm menopause or ovarian suppression; testosterone for men on ADT
- PSA for prostate cancer, to see whether treatment is working
- Gynecologic follow-up and prompt evaluation of any abnormal bleeding with tamoxifen
- Mammograms and regular follow-up visits after breast cancer
- Scans for advanced cancer, at intervals your team sets
Cost
Most breast cancer hormone pills (tamoxifen, letrozole, anastrozole, exemestane) are available as low-cost generics. Injections such as fulvestrant, goserelin and leuprolide, newer prostate cancer drugs, and targeted drugs given with hormone therapy are much more expensive. Ask your oncology social worker, pharmacist or financial navigator about insurance coverage, manufacturer assistance programs and nonprofit copay foundations. Never skip doses because of cost without telling your team.
Questions to Ask Your Care Team
- Is my cancer hormone receptor-positive (or hormone-sensitive)? How strongly?
- Which hormone therapy do you recommend, and why that one?
- How much will it lower my risk of the cancer coming back or growing?
- How long will I take it? Will we revisit that decision later?
- What side effects should I expect, and what can we do about them?
- Do I need a bone density scan? What should I do to protect my bones and heart?
- Which of my current medicines or supplements could interfere?
- What should I do if I want to get pregnant, or if I need surgery?
- Are there clinical trials I could join?
Frequently Asked Questions
What is the difference between hormone therapy and chemotherapy?
Chemotherapy kills fast-growing cells throughout the body, including cancer cells. Hormone therapy works only on cancers that use hormones to grow, by lowering or blocking those hormones. It usually has different side effects, such as hot flashes and joint pain rather than hair loss and low blood counts, and is often taken for years.
How long do you take hormone therapy for breast cancer?
Usually at least 5 years after surgery for hormone receptor-positive early breast cancer. Many people with a higher risk of recurrence are offered 7 to 10 years in total. For advanced breast cancer, it continues as long as it keeps the cancer under control.
Which is better, tamoxifen or an aromatase inhibitor?
After menopause, aromatase inhibitors such as letrozole, anastrozole and exemestane lower recurrence somewhat more than tamoxifen. Before menopause, tamoxifen is standard unless the ovaries are suppressed. The best choice also depends on side effects, bone health, and clot risk.
Does hormone therapy for prostate cancer cure it?
On its own, hormone therapy usually controls prostate cancer rather than curing it. Combined with radiation, it improves the chance of cure for many men with intermediate- or high-risk localized cancer. For advanced cancer, it can keep the cancer under control for years.
Can I stop hormone therapy if the side effects are too hard?
Talk to your care team before stopping. Most side effects have treatments, and switching to a different drug often helps. If you decide to stop, your team can explain how that changes your risk and what other options exist.
Does hormone therapy cause weight gain?
Androgen deprivation therapy for prostate cancer commonly leads to weight gain and muscle loss. For breast cancer, studies have not shown that tamoxifen or aromatase inhibitors directly cause much weight gain, though many people gain weight after treatment. Regular exercise, including strength training, helps.
Is hormone therapy the same as hormone replacement therapy?
No. Hormone replacement therapy adds estrogen to ease menopause symptoms. Cancer hormone therapy lowers or blocks hormones to slow cancer growth. HRT is usually avoided after hormone receptor-positive breast cancer.
Medical Disclaimer
This page is for education only and does not replace advice from your doctor, nurse or pharmacist. Treatment decisions depend on your specific cancer and health. Do not start, stop or change any medicine without talking to your care team. In an emergency, call 911.
Sources and References
- National Cancer Institute. Hormone Therapy to Treat Cancer. cancer.gov. Accessed October 2026.
- National Cancer Institute. Hormone Therapy for Breast Cancer; Hormone Therapy for Prostate Cancer. cancer.gov. Accessed October 2026.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology: Breast Cancer; Prostate Cancer. Current versions, accessed October 2026.
- Burstein HJ, et al. Adjuvant endocrine therapy for women with hormone receptor-positive breast cancer: ASCO clinical practice guideline focused update. J Clin Oncol. 2019;37(5):423-438.
- Allison KH, et al. Estrogen and progesterone receptor testing in breast cancer: ASCO/CAP guideline update. J Clin Oncol. 2020;38(12):1346-1366.
- Burstein HJ, et al. Endocrine treatment and targeted therapy for hormone receptor-positive, HER2-negative metastatic breast cancer: ASCO guideline update. J Clin Oncol. Current version.
- Early Breast Cancer Trialists' Collaborative Group. Aromatase inhibitors versus tamoxifen in early breast cancer: patient-level meta-analysis of the randomised trials. Lancet. 2015;386(10001):1341-1352.
- Francis PA, et al. Tailoring adjuvant endocrine therapy for premenopausal breast cancer (SOFT and TEXT). N Engl J Med. 2018;379(2):122-137.
- Hassett MJ, et al. Management of male breast cancer: ASCO guideline. J Clin Oncol. 2020;38(16):1849-1863.
- Virgo KS, et al. Initial management of noncastrate advanced, recurrent, or metastatic prostate cancer: ASCO guideline update. J Clin Oncol. 2021;39(11):1274-1305.
- Hershman DL, et al. Early discontinuation and nonadherence to adjuvant hormonal therapy in a cohort of 8,769 early-stage breast cancer patients. J Clin Oncol. 2010;28(27):4120-4128.
- Food and Drug Administration. Drug labels for tamoxifen, letrozole, anastrozole, exemestane, fulvestrant, leuprolide, degarelix and relugolix. DailyMed. Accessed October 2026.