Indications for radiation therapy for prostate cancer include clinical stages T1 to T4, M0 to M1. M0-stage prostate cancer patients undergo radiation therapy techniques including external beam radiation and brachytherapy. External beam radiation techniques comprise conventional radiation therapy, three-dimensional conformal radiation therapy, and intensity-modulated radiation therapy. Permanent seed implantation is used only for the treatment of early-stage localized prostate cancer with a good prognosis. External radiation therapy is divided into three categories based on therapeutic objectives: curative, adjuvant, and palliative radiation therapy.