Radiotherapy is one of the main curative treatments for localised and locally advanced prostate cancer, and for many men it is a viable alternative to surgery rather than a second-best option. Modern treatments include external beam radiotherapy (EBRT), stereotactic ablative radiotherapy (SABR), proton beam therapy, and internal radiotherapy techniques such as High Dose Rate (HDR) and Low Dose Rate (LDR) brachytherapy. Understanding the differences between these radiotherapy options is important. The best treatment depends on the stage and grade of the cancer, MRI and biopsy findings, urinary function, prostate size, general health and patient priorities.
Radiotherapy uses carefully planned high-energy radiation (typically X-rays) to destroy prostate cancer cells. Treatment is delivered either from outside the body using external beam radiotherapy and SABR, or from inside the prostate using brachytherapy. External beam radiotherapy is the most commonly used radiotherapy treatment for prostate cancer in the UK and is often delivered by image guided intensity modulated (IMRT) approaches which precisely sculpt radiation doses to the 3D shape of a tumor . NICE recommends offering 60 Gy in 20 fractions using IMRT unless this is unsuitable, and conventional schedules such as 74 Gy in 37 fractions remain an option where needed. IMRT reduces radiation exposure to nearby tissues such as the bladder and rectum. This makes treatment safer and helps reduce side effects compared with older techniques.
SABR delivers standard external beam radiotherapy with a small number of high-dose treatments. It is a form of ultra-hypofractionated radiotherapy, generally given in 5 treatments (rather than 20 treatments). The main attraction of SABR is convenience and avoiding the need for hormone treatment alongside. NHS England announced in June 2026 that eligible men with early-stage prostate cancer in England would be offered SABR in 5 sessions rather than the standard 20-fraction course, reflecting wider adoption of this approach. SABR is generally most relevant for men with localised low- or intermediate-risk prostate cancer, although suitability depends on anatomy, urinary symptoms, prostate size, imaging and local expertise.
Hormone therapy, also known as androgen deprivation therapy (ADT), is often used with radiotherapy for intermediate-risk, high-risk and locally advanced prostate cancer. It is given because lowering testosterone can make radiotherapy more effective by helping the X-rays break up the cancer DNA and improve cancer outcomes in the right setting. Patients will often hear the terms neoadjuvant, concurrent and adjuvant hormone therapy:
The duration of hormone therapy depends on the risk group and treatment plan. Shorter courses may be used in some intermediate-risk cases, while longer-term hormone therapy is commonly combined with external beam radiotherapy in high-risk or locally advanced disease.
Hormone therapy is not needed for every patient having radiotherapy, and part of a specialist consultation is working out who is likely to benefit enough to justify the side effects, which can include hot flushes, tiredness, sexual dysfunction and metabolic changes.
Instead of directing radiation from outside the body, the radiation source is placed inside the prostate in brachytherapy. There are two main forms:
For selected men with intermediate-risk prostate cancer and good urinary function, LDR brachytherapy may be used as a stand-alone treatment, however, is less popular nowadays due to SABR. In higher-risk disease, HDR brachytherapy is more commonly used as a boost in combination with external beam radiotherapy and hormone therapy rather than alone.
For many men with localised prostate cancer, radiotherapy and surgery are both good curative options. The decision often comes down to the cancer characteristics, age, fitness, urinary and sexual function priorities, tolerance of hormone therapy, and patient preference after informed discussion. Radiotherapy avoids an operation and anaesthetic, but treatment may extend over days or weeks and some men will also need hormone therapy. Surgery gives immediate removal of the prostate and full pathological assessment, but carries different trade-offs in relation to recovery, continence and erections.
If you are discussing prostate cancer radiotherapy, useful questions include:
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