Cancer is one of the leading causes of death worldwide . Currently, cancer patients survive longer than they did more than two decades ago, and the population living with cancer is increasing. Understanding more about cancer radiobiology and major developments in radiation therapy technology play a critical role in increasing the life expectancy of these patients. Radiation therapies are used with three different concepts in cancer that are defnitive, adjuvant, or palliative. It has been estimated that more than 50% of all cancer patients receive radiation therapy throughout the course of their disease . With new technological advancements in imaging and radiation delivery, radiation therapy has been possible for more complicated cases, increasing the rate of radiation therapy in cancer treatments. In addition to the tumor sterility and tumoricidal effects of radiation therapy ,radiation has the potential to affect normal tissues, which includes tissue damage in radiation therapy felds or systemic side effects (e.g., hematologic side effects,fatigue). Physicians try to lower radiation therapy side effects by defning smaller targets and using more dedicated machines, but side effects continue to occur and their spectrum and severity are changing. As these patients live longer, more attention is directed on their quality of life.