Hormone Therapy for Prostate Cancer: ADT, Drugs, Benefits & Side Effects

What Does “Hormone Therapy” Mean in Prostate Cancer?

Prostate cancer is strongly influenced by androgen-receptor signaling.

Testosterone is the main circulating androgen, while dihydrotestosterone (DHT) binds even more strongly to the androgen receptor.

Hormone therapy works by one or both of two broad strategies:

• lowering androgen production; and/or
• blocking androgen action at the cancer cell’s androgen receptor.

Because the goal is deprivation or blockade of androgen signaling, the most common medical term is androgen deprivation therapy (ADT).

Does Testosterone “Feed” Prostate Cancer?

That phrase is an oversimplification, but it captures an important biological principle.

Many prostate cancers initially depend heavily on androgen-receptor signaling. Lowering testosterone or blocking the androgen receptor can therefore suppress tumour growth.

However, hormone therapy does not simply “starve every cancer cell to death.” Over time, some cancer cells can adapt and continue growing despite very low testosterone. This is called castration-resistant prostate cancer (CRPC).

Importantly, even castration-resistant cancer often remains dependent on androgen-receptor pathways, which is why newer hormonal drugs can still work after ordinary ADT stops controlling the disease.

What Are the Main Types of Hormone Therapy?

1. GnRH/LHRH Agonists

GnRH agonists are long-established medical ADT drugs.

Examples include:

• leuprolide (Lupron Depot and other formulations);
• goserelin;
• triptorelin.

They initially stimulate the pituitary gland, causing a temporary increase in LH and testosterone. Continued treatment then desensitizes the pituitary GnRH receptors and suppresses testosterone production.

Testosterone Flare

The temporary testosterone rise can worsen symptoms in men with advanced disease.

Possible flare complications include:

• increased bone pain;
• urinary obstruction;
• ureteral obstruction;
• hematuria; and
• spinal cord compression.

Men at meaningful risk may receive short-term older-generation anti-androgen therapy around treatment initiation, or a GnRH antagonist may be preferred.

2. GnRH Antagonists

GnRH antagonists suppress testosterone without the initial hormonal surge.

Examples include:

• degarelix — injection; and
• relugolix — oral tablet.

They can be particularly attractive when rapid testosterone suppression is desirable or when clinical flare could be dangerous.

Current EAU guidance recommends a GnRH antagonist or orchiectomy at the start of ADT when impending complications such as spinal cord compression or bladder-outlet obstruction make a testosterone flare especially undesirable.

3. Orchiectomy

Bilateral orchiectomy is surgical removal of both testicles.

The testicles produce the great majority of circulating testosterone, so orchiectomy lowers testosterone rapidly and permanently.

NCI reports that surgical castration can reduce circulating testosterone by approximately 90–95%.

Advantages

• very rapid testosterone reduction;
• no repeated injections;
• no adherence problem;
• no testosterone flare; and
• potentially lower long-term treatment cost.

Disadvantages

• irreversible;
• permanent infertility;
• psychological/body-image impact for some men; and
• the same long-term consequences of profound androgen deprivation, including sexual, bone and metabolic effects.

Orchiectomy remains medically effective, but many men prefer reversible drug-based ADT.

4. Modern Androgen-Receptor Pathway Inhibitors

Modern prostate-cancer hormone treatment no longer ends with lowering testicular testosterone.

ARPIs suppress the androgen pathway more deeply.

Abiraterone

Abiraterone inhibits CYP17 and substantially reduces androgen synthesis from the adrenal glands and within prostate-cancer tissue.

It must be given with low-dose prednisone/prednisolone to reduce mineralocorticoid-related toxicity.

Important monitoring includes:

• blood pressure;
• potassium;
• fluid retention;
• liver function; and
• drug interactions.

Enzalutamide

Enzalutamide strongly inhibits androgen-receptor signaling.

Possible issues include fatigue, hypertension, falls, drug interactions and rare seizures.

Apalutamide

Apalutamide is another potent androgen-receptor inhibitor.

Possible effects include rash, fatigue, fractures/falls and hypothyroidism.

Darolutamide

Darolutamide is a potent androgen-receptor inhibitor with distinct pharmacologic properties and relatively limited blood-brain-barrier penetration.

It is used in selected hormone-sensitive metastatic and non-metastatic castration-resistant settings.

For a broader drug-by-drug overview, see prostate cancer drugs.

When Is Hormone Therapy Used?

The answer depends heavily on the cancer’s stage, Grade Group, PSA, imaging findings, recurrence pattern and life expectancy.

Localized Low-Risk Prostate Cancer

ADT is not routine treatment for low-risk localized prostate cancer.

Many men are better managed with active surveillance, while definitive local treatment is reserved for appropriate progression or higher-risk disease.

Hormone therapy should not be used simply because a man wants to avoid discussing standard local-treatment options.

Intermediate-Risk Disease Treated With Radiotherapy

For appropriate unfavorable intermediate-risk patients receiving conventional or moderately hypofractionated radiotherapy, EAU recommends short-term ADT for approximately 4–6 months.

Some favorable intermediate-risk patients treated with appropriate modern radiation can omit ADT.

This is why the legacy statement that hormone treatment is routinely used “before radiation in early cancer” is too broad.

High-Risk Localized Prostate Cancer

For high-risk localized disease treated with external-beam radiotherapy, current EAU guidance recommends:

radiotherapy + long-term ADT, generally 2–3 years.

This combined treatment improves cancer control compared with short-course ADT in appropriately selected high-risk patients.

Locally Advanced and Node-Positive Disease

Hormonal treatment is an important part of multimodal therapy.

Current EAU guidance recommends:

• long-term ADT for at least two years with radiotherapy in appropriate cN0 locally advanced disease;
• radiotherapy + long-term ADT + two years of abiraterone for selected cN0M0 patients with at least two major high-risk factors; and
• prostate/pelvic radiotherapy + long-term ADT + two years of abiraterone for cN1M0 disease.

After Radical Prostatectomy

ADT is not automatically given after surgery.

Some men with adverse pathology or lymph-node-positive disease may benefit from postoperative treatment, while others can be observed.

When PSA persists or later rises, salvage radiotherapy may be combined with short- or longer-duration hormonal treatment depending on:

• PSA level;
• Grade Group/Gleason score;
• pathology;
• PSA kinetics;
• imaging; and
• risk of further progression.

So the decision should be individualized rather than described as routine “insurance” after surgery.

Biochemical Recurrence

A rising PSA after surgery or radiotherapy does not automatically mean immediate lifelong ADT.

Management can include:

• observation in selected low-risk recurrence;
• salvage radiotherapy after prostatectomy;
• ADT combined with salvage treatment in selected higher-risk patients; and
• systemic therapy for patients at sufficiently high metastatic/progression risk.

PSA doubling time, pathology, imaging and life expectancy all matter.

Metastatic Hormone-Sensitive Prostate Cancer

This is where treatment has changed most dramatically.

For most fit men whose first presentation is metastatic (M1) prostate cancer, current EAU guidance says do not use ADT monotherapy when combination therapy is suitable.

Recommended options include ADT plus:

• abiraterone + prednisone;
• apalutamide;
• enzalutamide;
• darolutamide in appropriate patients; or
• other approved agents according to region and patient factors.

Selected chemotherapy-fit patients may receive:

ADT + docetaxel + an appropriate ARPI.

Selected men with newly diagnosed low-volume metastatic disease can also benefit from radiotherapy to the prostate as part of the treatment plan.

See our advanced prostate cancer guide.

Does ADT Continue When the Cancer Becomes Castration-Resistant?

Usually, yes.

Prostate cancer is called castration-resistant when it progresses despite a castrate testosterone level.

The traditional defining testosterone threshold is <50 ng/dL (1.7 nmol/L), although modern treatment often suppresses testosterone below 20 ng/dL.

ADT is generally continued while another treatment is added according to the patient’s:

• previous ARPI exposure;
• chemotherapy history;
• PSMA imaging;
• tumour genomics;
• symptoms;
• metastatic sites; and
• overall health.

What Are the Main Side Effects of ADT?

Profound testosterone suppression affects many organ systems.

Sexual Dysfunction

Loss of libido and erectile dysfunction are very common consequences of profound androgen deprivation.

This does not mean every man experiences the same degree of dysfunction.

Age, pre-treatment erections, cardiovascular health, diabetes, other medicines and additional cancer treatments all affect sexual function.

Hot Flashes

Hot flashes can occur after either medical or surgical castration and may persist during long-term treatment.

When severe, they can interfere with sleep and quality of life. Treatment options are available and should be discussed rather than simply tolerated indefinitely.

Muscle Loss and Weight Gain

ADT changes body composition:

• lean muscle mass tends to decline;
• body fat tends to increase; and
• physical fitness can decline.

Regular resistance and aerobic exercise are among the most useful supportive measures.

Bone Loss and Fracture Risk

ADT accelerates loss of bone mineral density.

Current EAU guidance recommends a baseline DEXA bone-density scan when long-term ADT starts.

Bone health management may include:

• weight-bearing and resistance exercise;
• adequate calcium and vitamin D;
• smoking cessation;
• limiting excess alcohol;
• fracture-risk assessment; and
• denosumab or bisphosphonate therapy when clinically indicated.

If no bone-protective treatment is given, EAU recommends repeated DEXA monitoring at least every two years during long-term ADT.

Diabetes and Metabolic Syndrome

ADT reduces insulin sensitivity and increases the risk of metabolic abnormalities.

Current EAU follow-up guidance recommends checking:

• fasting glucose;
• HbA1c;
• lipid profile;
• blood pressure; and
• weight/body composition.

Men with existing diabetes or impaired glucose tolerance may need closer management.

Cardiovascular Health

The old article warned that long-term hormone therapy “causes a lot of cardiovascular problems.” That wording is too absolute.

A more accurate statement is:

ADT is associated with metabolic and cardiovascular risk, particularly in men who already have cardiovascular disease or multiple risk factors.

EAU recommends:

• cardiovascular risk assessment before treatment;
• baseline ECG;
• regular blood-pressure/metabolic monitoring; and
• at least cardiology consultation for men with a history of cardiovascular disease.

Mood and Cognitive Effects

Some men experience:

• depression;
• reduced motivation;
• sleep disruption;
• fatigue; or
• cognitive complaints.

These symptoms may also be influenced by cancer itself, age, sleep disturbance, anemia, medications and other illnesses.

Persistent mood or cognitive changes should be discussed with the treatment team.

How Is Hormone Therapy Monitored?

ADT follow-up should assess both the cancer and treatment toxicity.

Current EAU guidance recommends monitoring:

• PSA;
• testosterone;
• hemoglobin;
• kidney function/creatinine;
• liver function;
• alkaline phosphatase where appropriate;
• lipid profile;
• fasting glucose/HbA1c;
• blood pressure and cardiovascular risk;
• bone mineral density;
• symptoms and quality of life; and
• imaging according to disease stage.

Men on ADT are generally reviewed every 3–6 months, although patients beginning combination therapy may require more frequent early monitoring.

Why Testosterone Monitoring Matters

PSA alone is not enough.

EAU considers testosterone monitoring standard clinical practice during ADT because some men do not achieve or maintain an adequate castrate level.

If PSA rises or the cancer appears to progress, testosterone should be measured before calling the disease castration-resistant.

Intermittent vs Continuous ADT

Intermittent ADT means stopping treatment for periods when the cancer is well suppressed, allowing testosterone to recover before treatment is restarted according to predefined criteria.

This can improve some quality-of-life effects in selected men.

However, the strongest modern survival evidence for metastatic treatment intensification with ARPIs has been generated using continuous ADT.

Intermittent therapy should therefore be a deliberate specialist strategy—not simply missed injections or self-directed treatment breaks.

Can Hormone Therapy Cure Prostate Cancer?

The answer depends on context.

ADT alone usually does not cure metastatic prostate cancer.

But when ADT is combined with definitive radiotherapy in selected non-metastatic intermediate-, high-risk or locally advanced disease, it can be an important component of treatment given with curative intent.

That is why describing hormone therapy as either “a cure” or “only palliation” is too simplistic.

What Happens If Hormone Therapy Stops Working?

If cancer progresses despite adequately suppressed testosterone, the disease becomes castration-resistant.

Modern options can include:

• androgen-receptor pathway inhibitors;
• docetaxel or cabazitaxel chemotherapy;
• PARP-based therapy for selected genomic alterations;
• PSMA-targeted radioligand therapy;
• radium-223 in selected bone-predominant disease;
• sipuleucel-T in selected patients; and
• other biomarker-directed treatments.

See our prostate cancer medication overview and latest prostate cancer treatments.

Questions to Ask Before Starting ADT

1. Why is hormone therapy indicated for my exact cancer stage and risk group?
2. How long will I need ADT?
3. Should I receive an agonist, antagonist or consider orchiectomy?
4. Am I at risk of testosterone flare?
5. Should another treatment such as abiraterone, enzalutamide, apalutamide, darolutamide or docetaxel be added?
6. What are my baseline PSA and testosterone?
7. Do I need a DEXA scan?
8. How will my glucose, cholesterol and cardiovascular health be monitored?
9. What can I do to reduce muscle and bone loss?
10. How will treatment affect my sexual function and quality of life?

Medical information notice: Hormone therapy for prostate cancer is highly stage-specific. Drug selection, duration and combination treatment should be determined by the oncology/urology team rather than started, stopped or interrupted based on general online information.