Using radiotherapy (radiation therapy) as a method of treating prostate cancer reduces fatal cases by more than 40%, a study shows. It was conducted by British and Canadian scientists and funded by the UK’s Medical Research Council. Radiotherapy uses high-energy X-rays to kill cancer cells and shrink the tumor. Radiation can be delivered via an external source (external radiotherapy) or via radioactive beads directly into the tumor (internal or brachytherapy). Adding radiation therapy to standard hormonal treatment reduced fatal cases of locally advanced prostate cancer by 43% over a six-year period, researchers found. In locally advanced prostate cancer, the spread of the cancer to neighboring organs or metastasis to the regional lymph nodes is characteristic. There are also risks associated with radiotherapy. They are usually directly related to the administered dose and depend on the site of administration. The most common side effects are fatigue, decreased appetite, redness of the skin. A decrease in the number of white blood cells is also observed. The study was published in The Lancet.