Radiotherapy treats cancer by using high-energy x-rays to destroy the cancer cells, while doing as little harm as possible to normal cells.
Radiotherapy for prostate cancer is usually given from an external machine (external beam radiotherapy), but for some men with early prostate cancer it can be given by inserting small radioactive seeds into the tumour (brachytherapy).
External radiotherapy and brachytherapy both appear to be equally effective in curing prostate cancer. In many cases your doctor may suggest that you have hormonal therapy before or after your radiotherapy.
When radiotherapy is used
In early prostate cancer, the radiotherapy is given to the prostate gland. The aim is to destroy the cancer cells, while doing as little harm as possible to normal tissues in the surrounding area such as the bladder or back passage (rectum). This is known as radical radiotherapy.
As with all treatments there can be side effects, if you are worried make sure your doctor has explained everything, or call the Cancerbackup helpline on 0808 800 1234 for more information