Author: The Focal Therapy Clinic
Length: 8 min read
Published: 14 May 2025
Medically Reviewed: By Dr Aqua Asif

At a Glance

Testosterone replacement therapy (TRT) may be considered for carefully selected men after treatment for localised prostate cancer, but it is not appropriate for everyone. Current evidence does not show that TRT causes prostate cancer in men with confirmed testosterone deficiency, though long-term safety data in cancer survivors remain limited. Any decision requires full specialist review, including PSA monitoring and assessment of cancer history.

Key takeaways

  • Who may be considered: Men with confirmed low testosterone, low-risk treated prostate cancer, stable PSA, and no evidence of active disease.
  • Historical concern addressed: earlier fears that testosterone fuels cancer came from studies in advanced disease; the saturation model has shifted thinking, but caution remains warranted.
  • Evidence is limited: most supporting studies are small and retrospective; results cannot be applied to all men.
  • Monitoring is essential: PSA, testosterone level, full blood count, and haematocrit should be checked regularly during TRT.
  • Not suitable for everyone: TRT is usually avoided with active, locally advanced or metastatic prostate cancer. Specialist review is essential before starting.
  • TRT after radiotherapy: needs extra caution because PSA does not usually fall to zero.

Why the historical concern about testosterone?

For many years, doctors were cautious about testosterone in men with prostate cancer.

This concern came from the fact that prostate cancer cells often use male hormones, called androgens, to grow. Testosterone is the main male hormone.

A major prostate cancer treatment is androgen deprivation therapy. This lowers testosterone to slow cancer growth. It is often used for advanced prostate cancer, or alongside radiotherapy in some higher-risk cases.

It was therefore assumed that giving testosterone back could ‘fuel’ prostate cancer. That was a reasonable concern at the time.

However, the older evidence mainly came from men with advanced disease. It did not answer a different question: whether TRT is safe in carefully selected men with treated, localised prostate cancer and stable follow-up results.

Modern evidence has challenged the idea that more testosterone always means more prostate cancer growth. One theory is called the saturation model. This suggests prostate tissue may respond to testosterone only up to a certain level.

The saturation model is useful, but it is not a guarantee of safety. It does not remove the need for careful selection and monitoring.

What does recent evidence show?

Recent studies suggest TRT does not appear to increase the risk of developing prostate cancer in men who are properly diagnosed with testosterone deficiency.

Evidence is more cautious in men who have already had prostate cancer. Some studies suggest that selected men may use TRT after successful treatment for localised prostate cancer without a clear increase in recurrence. This is most reassuring in men with low-risk disease, favourable pathology and stable PSA results.

However, long-term evidence is still limited. Many studies are small, retrospective, and include carefully selected patients. This means the results cannot be applied to every man.

The European Association of Urology advises caution. It states that TRT may be discussed in symptomatic men previously treated for prostate cancer, but this needs full counselling and careful selection.

Who might benefit from TRT?

TRT may be considered when a man has both symptoms and confirmed low testosterone.

Possible symptoms include:

  • low sex drive
  • fewer morning erections
  • erectile difficulties
  • low energy
  • low mood
  • reduced muscle strength
  • increased body fat
  • poor concentration
  • reduced bone strength

It is very important to note that these symptoms can have many causes. Stress, poor sleep, depression, diabetes, obesity, medicines and cancer treatment can all contribute.

This is why blood testing matters especially here. A diagnosis usually needs at least two morning testosterone blood tests. Your doctor may also check free testosterone, sex hormone binding globulin, luteinising hormone, follicle-stimulating hormone and prolactin. A specialist should interpret these results.

What monitoring is required?

Monitoring is essential before and during TRT.

Your clinician may check:

  • PSA
  • testosterone level
  • full blood count, especially haematocrit
  • blood pressure
  • weight and waist size
  • cholesterol and blood sugar
  • symptoms and side effects
  • urinary symptoms
  • heart risk factors

Haematocrit means the proportion of your blood made up by red blood cells. TRT can raise haematocrit. If it becomes too high, treatment may need to be reduced, paused or changed.

For men with previous prostate cancer, PSA is especially important. Many guidelines advise checking PSA at three, six and 12 months during the first year of TRT, then at least yearly after that.

Your monitoring plan may be more intensive if you have had prostate cancer.

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    What are the potential benefits of TRT?

    When TRT is suitable, the aim is to improve symptoms caused by low testosterone.

    Possible benefits may include:

    • improved sex drive
    • better morning erections
    • improved energy
    • improved mood in some men
    • increased lean muscle mass
    • reduced fat mass
    • improved bone density
    • correction of unexplained anaemia in some men

    TRT is not a general anti-ageing treatment. It is not recommended for men with normal testosterone levels.

    Sexual recovery after prostate cancer treatment is also complex. TRT may help desire if testosterone is low. Erections also depend on nerves, blood flow, medication response and the type of prostate cancer treatment received.

    When might TRT be avoided?

    TRT is not suitable for everyone.

    It is usually avoided in men with:

    • active prostate cancer where TRT is not considered safe
    • locally advanced or metastatic prostate cancer
    • unexplained rising PSA
    • suspicious MRI or biopsy findings
    • male breast cancer
    • high haematocrit
    • severe unstable heart disease
    • severe chronic heart failure
    • untreated severe sleep apnoea
    • a current wish to have children

    TRT can reduce sperm production. Men who want children may need different options. TRT is also not appropriate for men receiving androgen deprivation therapy for prostate cancer. These two treatments have opposite aims.

    This is why testosterone replacement therapy and prostate cancer should never be managed through online shortcuts or non-specialist prescribing. Safe care depends on proper diagnosis and structured follow-up. Expert oversight protects patients.

    The Focal Therapy Clinic approach

    The Focal Therapy Clinic provides specialist assessment for men with localised prostate cancer.

    Many patients want effective cancer control while reducing avoidable side effects. Our team focuses on precision-led care and personalised treatment planning.

    For suitable men, focal therapy aims to treat the known cancer area rather than the whole prostate. It aims to reduce damage to nearby healthy tissue and aims to preserve urinary continence and erectile function. TRT decisions after prostate cancer need careful review. This is especially true after focal therapy, because healthy prostate tissue remains and PSA monitoring differs from surgery.

    Every case needs to be considered in context. The right plan depends on the cancer, previous treatment, testosterone levels, symptoms, PSA pattern, MRI findings and personal priorities.

    The clinic offers minimally invasive treatments including HIFU and NanoKnife for suitable patients. Every case is reviewed through a multidisciplinary team that includes experts in surgery, oncology, imaging, and male health. With more than 2000 patients treated with focal therapy and decades of combined experience, the clinic also provides trusted second opinions for men comparing their options.

    FAQs

    Q: Does testosterone replacement therapy cause prostate cancer?
    A: Current evidence does not show that TRT causes prostate cancer in men with confirmed testosterone deficiency. However, men still need proper assessment before starting treatment. This currently includes PSA testing and specialist review if prostate cancer risk is raised.
    Q: Is TRT safe after prostate cancer treatment?
    A: It may be considered for selected men after treatment for localised prostate cancer on a case-by-case basis. This is most likely when the cancer was low risk, treatment results are reassuring, and PSA has stayed stable over time. Safety data are still limited, so specialist counselling is important.
    Q: What PSA changes should I expect on TRT?
    A: Some men have a small PSA rise after starting TRT. This does not always mean cancer has returned. Persistent or rapid PSA rises need specialist assessment. TRT can also raise haematocrit, which is why full blood count monitoring is important.
    Q: How often should PSA be monitored during TRT?
    A: Monitoring schedules vary by clinician and patient history. Many men are checked more frequently during the first year of treatment. Men with previous prostate cancer may need closer monitoring. Ongoing review continues after that.
    Q: When is TRT absolutely contraindicated?
    A: TRT is usually avoided in men with active, locally advanced or metastatic prostate cancer. It may also be avoided with male breast cancer, high haematocrit, severe unstable heart disease, severe chronic heart failure, or if you are trying to have children.

    References

    European Association of Urology. (2026). EAU Guidelines on Prostate Cancer. Available at: https://uroweb.org/guidelines/prostate-cancer

    National Institute for Health and Care Excellence. (2021). Prostate cancer: diagnosis and management (NG131). Available at: https://www.nice.org.uk/guidance/ng131

    Bhasin, S., et al. (2023). Prostate safety events during testosterone replacement therapy in men with hypogonadism: a randomized clinical trial. JAMA Network Open, 6(12), e2348692.

    Santucci, J., et al. (2025). Oncological safety of testosterone replacement therapy in men with localised prostate cancer: a systematic review of observational studies. BJU International, 136(5), 788–799.

    Morgentaler, A. and Traish, A.M. (2009). Shifting the paradigm of testosterone and prostate cancer: the saturation model and the limits of androgen-dependent growth. European Urology, 55(2), 310–320.

    Edison, M.A., et al. (2026). Testosterone Replacement Therapy in Hypogonadal Men with a Prostate Cancer Diagnosis: A British Society for Sexual Medicine Consensus Statement. World Journal of Men’s Health, 44(1), 5–22.

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