3. Radiation therapy “uses high-energy rays or particles to kill cancer cells,” explains the American Cancer Society. It may be used “as the first treatment for low-grade cancer that is still just in the prostate gland,” which has similar cure rates to radical prostatectomy. But also “as part of the first treatment for cancers that have grown outside of the prostate gland and into nearby tissues. There are two main types of radiation therapy for patients with prostate cancer. (Read more about radiation therapy)