Hormone therapy, also known as Androgen Deprivation Therapy (ADT), is a cornerstone of prostate cancer treatment in the UK. Because prostate cancer cells typically rely on testosterone to grow and multiply, reducing the levels of this hormone can effectively shrink tumours or slow their progression. While hormone therapy is not usually a cure on its own, it is a powerful tool used at various stages of the cancer journey, from enhancing the success of radiotherapy to managing advanced disease. Understanding its role helps patients and their families navigate the treatment process with confidence.
What We will cover in this Article
- The biological link between testosterone and prostate cancer growth
- How hormone therapy is used alongside radiotherapy (neoadjuvant therapy)
- The role of ADT in managing advanced or metastatic prostate cancer
- Common types of hormone treatments, including injections and tablets
- Managing the systemic side effects of reduced testosterone
- The transition to ‘hormone relapsing’ or ‘castrate resistant’ prostate cancer
How does hormone therapy work?
Hormone therapy works by depriving prostate cancer cells of the testosterone they need to survive. Testosterone is an androgen, a type of hormone that acts like ‘fuel’ for prostate cancer. By lowering the amount of testosterone in the body or blocking it from reaching the cancer cells, the treatment can cause the cancer to shrink or stop growing. This can lead to a significant drop in PSA (Prostate Specific Antigen) levels and provide long term control of the disease.
In the UK, hormone therapy is administered in several ways:
- LHRH Agonists and Antagonists: Injections or small implants under the skin that stop the testicles from producing testosterone.
- Anti-androgens: Tablets that stop testosterone from reaching the cancer cells.
- Abiraterone and Enzalutamide: Newer, high potency tablets used for more advanced cases to block testosterone production from other sources like the adrenal glands.
When is hormone therapy used?
Hormone therapy is used in different clinical scenarios depending on the stage of the cancer and the overall treatment goal.
| Clinical Scenario | Goal of Hormone Therapy | Typical Duration |
| With Radiotherapy | To shrink the tumour and make radiation more effective at killing cancer cells. | 6 months to 3 years. |
| Before Surgery | Occasionally used to shrink a tumour before a prostatectomy. | 3 to 6 months. |
| Biochemical Recurrence | Used if PSA levels begin to rise again after surgery or radiotherapy. | Intermittent or long term. |
| Advanced Cancer | The primary treatment to control cancer that has spread to other parts of the body. | Long term / Lifelong. |
Managing the side effects of ADT
Because testosterone plays a vital role in many bodily functions, reducing it leads to a range of systemic side effects. These can impact physical health and emotional wellbeing, but many can be managed with the support of your clinical team.
Physical Impacts:
- Hot Flushes: Sudden feelings of heat and sweating, similar to the menopause.
- Fatigue: A significant and persistent feeling of tiredness that rest does not always fix.
- Weight Changes: An increase in body fat, particularly around the waist, and a loss of muscle mass.
- Bone Health: Long term use can lead to thinning of the bones (osteoporosis), increasing the risk of fractures.
Sexual and Emotional Impacts:
- Loss of Libido: A significant decrease in sexual desire and interest.
- Erectile Dysfunction: Difficulty achieving or maintaining an erection.
- Mood Swings: Feeling more emotional, irritable, or experiencing symptoms of low mood and anxiety.
Monitoring and ‘Hormone Resistance’
When you start hormone therapy, your PSA levels are monitored closely to ensure the treatment is working. For most men, PSA drops significantly and remains low for a long period. However, over time, some prostate cancers can find ways to grow even when testosterone levels are very low. This is known as ‘hormone relapsing’ or ‘castrate resistant’ prostate cancer.
If this happens, it does not mean that treatment options have run out. In the UK, urologists and oncologists can switch to newer, ‘second generation’ hormone therapies or suggest other treatments such as chemotherapy or radium 223. The goal remains to keep the cancer stable and maintain the best possible quality of life.
Differentiation: Agonists vs. Antagonists
There are two main types of injections used to lower testosterone, and they work in slightly different ways.
LHRH Agonists (e.g., Goserelin/Zoladex):
These initially cause a brief ‘flare’ or spike in testosterone before the levels drop. To prevent this flare from worsening symptoms, patients are usually given a short course of anti androgen tablets for the first few weeks.
LHRH Antagonists (e.g., Degarelix/Firmagon):
These work more quickly and do not cause a testosterone flare. They are often used if a rapid drop in testosterone is needed, such as when cancer is putting pressure on the spinal cord or causing severe bone pain.
My final conclusion
Hormone therapy is a highly effective and essential part of prostate cancer care in the UK, providing vital control over the disease at multiple stages. While the side effects of low testosterone can be challenging, they are a trade off for the powerful impact the treatment has on shrinking tumours and slowing cancer growth. With the support of a multi disciplinary team, most men can manage these side effects and maintain a good quality of life while on treatment. If you are starting hormone therapy, discussing a management plan for side effects early on will help you stay active and well throughout your care.
If you experience severe, sudden, or worsening symptoms, such as new or severe bone pain or weakness in your legs, call 999 immediately.
How long does it take for hormone therapy to work?
PSA levels usually begin to fall within a few weeks of starting treatment, and physical symptoms of advanced cancer, such as bone pain, often improve shortly after.
Will I be on hormone therapy forever?
It depends on your diagnosis; for localised cancer, it is often a fixed course, but for cancer that has spread, it is typically a long term treatment.
Does hormone therapy cause weight gain?
Yes, it is very common to gain weight and lose muscle mass; staying active and following a healthy diet can help manage these changes.
Can I still have sex while on hormone therapy?
Many men experience a significant drop in desire and physical ability, but treatments for erectile dysfunction can still be effective for some.
What is a ‘testosterone flare’?
A temporary rise in testosterone that can happen when starting certain injections; it is managed by taking anti androgen tablets for a short period.
Does hormone therapy cause breast growth?
Some types of hormone therapy can cause breast tenderness or swelling (gynaecomastia); your doctor can suggest treatments to prevent or manage this.
Will my energy levels return after treatment?
If you are on a fixed course, your testosterone levels and energy usually begin to recover a few months after the last injection or tablet.
Authority Snapshot
This article was written and reviewed by Dr. Stefan Petrov, a UK trained physician with an MBBS and extensive experience in general medicine, surgery, and emergency care. Dr. Petrov has worked in various clinical environments, including surgical wards and intensive care units, where he has managed patients through complex cancer treatment pathways. This guide provides a medically accurate and neutral overview of hormone therapy for prostate cancer, adhering to current NHS and NICE clinical standards to support patient understanding and safety.
