Review: Radiation Therapy

Two major types of radiation therapy are external beam radiation therapy and internal radiation therapy. External beam radiation therapy delivers radiation from a source at a distance from the body and is directed at the cancer site. Internal radiation therapy places radiation sources as close as possible to the tumor site. There are several sub-categories of internal radiation therapies based on the way radiation is placed inside the body: interstitial, intracavitary, intraluminal, and intravenously.

Radiation therapy is often used when surgery is impossible or part or all of an organ would be removed if curative surgery were performed. Radiation therapy is most effective on radiosensitive cells.

As a neoadjuvant therapy, radiation therapy is used to reduce the size of the tumor and destroy cancer cells before surgical treatment and as adjuvant therapy destroy microscopic cancer cells after surgical treatment. Lower doses of radiation are given to cancer patients for palliative care purposes, most often given to bony metastases.

Researchers are always seeking new options for cancer treatment for cancers with limited treatment options, for option to treat cancers with less morbidity related to the treatment, and to find options to prevent cancer, delay recurrence, and extend remission interval. Prior to any new treatments being used, safety and efficacy must be established, this is accomplished via clinical trials.

Updated: December 21, 2023