External-beam radiotherapy treats cancer by using high-energy x-rays to destroy cancer cells, while doing as little damage as possible to normal cells. It’s the most common way of giving radiotherapy for locally-advanced prostate cancer. It is usually given with hormonal therapy.
The treatment is given in the hospital radiotherapy department. It’s usually given as daily sessions from Monday–Friday, with a rest at the weekend. The course of treatment may take up to eight weeks.