Radiotherapy uses radiation (eg high energy x-rays) either beamed from a machine (external-beam radiotherapy) or emitted by small radioactive ‘seeds’ implanted in the prostate (internal radiotherapy or brachytherapy), to kill cancer cells and shrink tumours.

If your prostate cancer is localised, your doctor may recommend radiotherapy as an alternative to surgery. External-beam radiotherapy is commonly used to treat prostate cancer that has spread too widely in the pelvis to be removed surgically but has not spread to the lymph nodes (lymph nodes are found throughout the body and produce white blood cells that fight infection). It may be used in combination with hormonal therapy (see Hormonal Therapy), when cancer cells have spread beyond the prostate and into the pelvic area (Stage III).  In advanced prostate cancer, radiotherapy can help to shrink tumours and relieve pain.

Figure 1: External-beam-radiotherapy

Brachytherapy targets cancer cells without harming the surrounding tissues and is not often recommended when the cancer has spread beyond the prostate gland. Brachytherapy may be used alone or can be combined with hormonal therapy or external-beam radiation therapy.

Figure 2: Brachytherapy