Approximately 50% of cancer patients receive some type of radiation therapy (also known as radiotherapy) during their cancer treatment. Radiation can be used on its own or in combination with chemotherapy, surgery, or hormone therapy. It is completely painless and is usually given once a day for between one day and eight weeks.
Normal cells grow and divide to form new cells. Cancer cells grow and divide faster than most normal cells. Radiation works by making small breaks in the DNA inside cells as they are dividing. This makes cancer cells a lot more vulnerable to radiation than normal cells, as they divide more often. These breaks in the DNA keep cancer cells from growing and dividing, causing them to die.
The goal of radiation therapy is to destroy cancer cells and/or slow tumor growth without harming nearby healthy tissue.
The most common type of radiation is called external-beam radiation therapy, which is given from a machine located outside the body. Types of external-beam radiation therapy include proton therapy, 3-dimensional conformal radiation therapy (3D-CRT), intensity-modulated radiation therapy (IMRT), and stereotactic radiation therapy (SRS or SBRT). Radiation can also be given using implants – this is called internal radiation therapy or brachytherapy.
Radiation can be used by itself to make the cancer shrink or completely go away. In some cases, chemotherapy may be given first. For other cancers, radiation may be used before surgery to shrink the tumor or after surgery to help keep cancer from coming back.
If you need radiation therapy, your first radiation therapy session is called a simulation and does not involve actual treatment. During this visit, your radiation team will position your body and then take a scan with a CT-scanner. At this time a technique may be used to note your position, such as permanent tattoos or temporary skin marks. These marks or technology are used to help the radiation team set up you up correctly for every treatment. Your treatment will begin a few days after simulation.
Treatment is usually given once a day for between 1 day and 8 weeks. It typically takes five 30-minutes sessions (or a “fraction” as the doctor may call it). It is important that you try to stay in exactly the same position as during your simulation. Many clinics now use AlignRT® to assist them in ensuring you are in the right position.
Hypofractionation is an advanced treatment technique that is becoming a standard of care for lung, breast, and prostate cancer patients. Using hypofractionation, or hypofractionated radiation therapy, higher doses of radiation are delivered over a shorter timeframe, so patients can complete their course of radiation therapy much faster than conventional treatments.
Some patients are eligible for extreme hypofractionation or SBRT (stereotactic body radiation therapy), which, when appropriate, can shave weeks off the traditional treatment length. Because each cancer type requires a different approach, each patient’s treatment plan is customized to their unique needs and treatment goals.
The side effects of radiation therapy vary and depend on the type and location of cancer, treatment dose, and your overall health. Side effects may include fatigue, skin reactions, upset stomach, and loose bowel movements. These often begin during the second or third week of treatment and may last for several weeks after the final radiation. Most side effects go away after treatment, although some long-term side effects may occur months after or years after treatment. Be sure to discuss the potential side effects with your doctors. More side effect information
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