What is external beam radiotherapy?

You have external-beam radiotherapy as an outpatient in the radiotherapy department. Radiotherapy is given using a machine that is like a big x-ray machine. This is called a linear accelerator (often called a LINAC).

You usually have it as a series of short, daily treatments. The treatments are given from Monday to Friday, with a rest at the weekend. Your course of treatment may last for 4 to 8 weeks. Radiotherapy is not painful, but you will need to lie still while you have it.

Some men may have radiotherapy over 4 weeks instead of over 7 weeks. The total dose of radiation is the same for both. But when it is given over 4 weeks, the dose for each treatment session is higher. Doctors call this hypofractionation. Both are effective treatments. Your cancer doctor will recommend the best timing and way for you to have your radiotherapy.

The radiotherapy does not make you radioactive. It is safe for you to be with other people during external radiotherapy, including children.

Advantages and disadvantages of external-beam radiotherapy

Radiotherapy and radical prostatectomy are both treatments that may cure early prostate cancer. They are equally effective in treating the cancer. To choose the treatment that is best for you, it can help to look at the different advantages and disadvantages of each one. You can then make your decision in partnership with your doctor.

Advantages of external-beam radiotherapy

  • You do not need an operation or a general anaesthetic, which may have risks.
  • You can carry on doing most of the daily things you usually do.
  • Urinary problems may happen less often than after surgery.

Disadvantages of external-beam radiotherapy

  • You have to go to hospital for 4 to 8 weeks, Monday to Friday, as an outpatient.
  • It can cause different side effects and some men may get bowel late effects.
  • It may be some time before doctors know if treatment has been successful.
  • If the cancer comes back after radiotherapy, it is more difficult to have surgery to remove the prostate.

PSA levels after external radiotherapy

After radiotherapy it can take time for your PSA level to drop. It usually goes down gradually. It may not get to its lowest level until about 18 months or longer after treatment. Your doctor and specialist nurse can give you more information about this.

Back to External beam radiotherapy explained