External beam radiation therapy (EBRT)
External beam radiation therapy (EBRT) is a medical treatment that employs high-energy radiation beams or radioactive sources, such as cobalt-60, to target and kill cancer cells by altering their genetic material. This therapy is widely utilized, with approximately 50 to 60 percent of cancer patients receiving radiation as part of their treatment plan. EBRT can be administered as a standalone curative option or in combination with other treatments like chemotherapy and surgery.
Before treatment, patients undergo a consultation and simulation process to accurately plan the radiation dose and determine the specific area to be treated. Various techniques are employed in EBRT, including 3D conformal radiation therapy, intensity-modulated radiation therapy (IMRT), and stereotactic radiosurgery, among others. Treatment typically spans one to ten weeks, with sessions scheduled five days a week.
While EBRT is designed to minimize damage to surrounding healthy tissues, some risks include localized skin reactions, fatigue, and the potential development of a second cancer. However, the primary goal of EBRT is to effectively kill cancer cells and reduce tumor size, contributing to improved patient outcomes.
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Subject Terms
External beam radiation therapy (EBRT)
ALSO KNOWN AS: Radiotherapy
DEFINITION: External beam radiation therapy (EBRT) uses a linear accelerator to generate high-energy radiation beams or a machine with a radioactive source, cobalt 60, to kill cancer cells by altering their genetic material. Particles that makeup EBRT include protons, electrons, and photons, such as X-rays and gamma rays.
Cancers treated: Most cancers, with approximately 50 to 60 percent of all cancer patients receiving radiation
Why performed: EBRT is a curative treatment alone or can be combined with chemotherapy, surgery, and other treatments. EBRT may also be used to treat symptoms or side effects from cancer, such as spinal cord compression and metastases.
Patient preparation: The patient will be referred to a radiation oncologist for a consult visit to determine if external beam radiation therapy is appropriate. Before receiving treatment, patients have a simulation using a computed tomography (CT) scanner or other device to visualize the area to be treated. A simulation may take one to two hours. Small marks may be applied to the skin to assist in positioning the radiation beams. The simulation data are used to plan the radiation dose amounts to be given by the linear accelerator. Accurate tumor targeting is the key to protecting normal tissues while killing cancer cells.
Patients and healthcare professionals work together to decide which type of EBRT is best—3D conformal radiation therapy, intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), tomotherapy/helical tomotherapy, intraoperative radiation (IORT), stereotactic body radiation therapy (SBRT), or stereotactic radiosurgery like Gamma Knife surgery.
Steps of the procedure: The treatment plan will outline the patient's position on the treatment table, define the number of treatments to be given, and prescribe the daily total dose. The patient usually has one to ten weeks of treatment, five days a week, with two days off for normal cells to rest and recover. The patient may need to change into a hospital gown. The staff will position the patient carefully in the treatment room and then leave the room to program the linear accelerator with the required treatment data. The total positioning and radiation administration time is about fifteen to thirty minutes.
After the procedure: Treatments are commonly outpatient, and the patient may leave immediately after the daily treatment. Patients are not radioactive following treatments.
Risks: External beam radiation therapy is a local treatment, so risks are generally associated with the treatment site. Skin reactions, similar to sunburn, may occur. Fatigue is often associated with EBRT, but the cause is unknown. There is a risk of a second cancer caused by the radiation. There is also a risk that the radiation will not kill all the cancer cells.
Results: External beam radiation therapy is expected to kill cancer cells and thus reduce tumor size.
Bibliography
Dupin, Charles, et al. "Treatment of Head and Neck Paragangliomas with External Beam Radiation Therapy." International Journal of Radiation Oncology, no. 89, vol. 2, 2014, pp. 353–59.
"External Beam Radiation Therapy (EBRT)." City of Hope, 29 Apr. 2022, www.cancercenter.com/treatment-options/radiation-therapy/external-beam-radiation. Accessed 20 July 2024.
"External Beam Radiation Therapy (EBRT)." Cleveland Clinic, 8 Sept. 2022, my.clevelandclinic.org/health/treatments/24008-external-beam-radiation-therapy-ebrt. Accessed 20 July 2024.
Halperin, Edward C., et al. Perez and Brady's Principles and Practice of Radiation Oncology. 7th ed., Lippincott-Wolters, 2019.
Koka, Krishna, et al. "Technological Advancements in External Beam Radiation Therapy (EBRT): An Indispensable Tool for Cancer Treatment." Cancer Management and Research, 2022, pp. 1421-1429. doi.org/10.2147/CMAR.S351744.
Moghaddam, Fahimeh Faghihi, et al. "Clinical Effectiveness Of Combined Whole Body Hyperthermia and External Beam Radiation Therapy (Ebrt) Versus Ebrt Alone in Patients with Painful Bony Metastases: A Phase Iii Clinical Trial Study." Journal of Thermal Biology, vol. 120, 2024, doi.org/10.1016/j.jtherbio.2024.103804.
Sperduto, Paul W., and John P. Gibbons. Khan’s Treatment Planning in Radiation Oncology. 5th ed., Wolters Kluwer, 2022.
Symonds, Paul, et al. Walter & Miller's Textbook of Radiotherapy: Radiation Physics, Therapy and Oncology. 8th ed., Churchill-Elsevier, 2019.
Videtic, Gregory M. M., et al. Handbook of Treatment Planning in Radiation Oncology. 3rd ed., Demos Medical, 2021.