Radiation therapy to treat and cure cancer is usually given every day, Monday through Friday, for about five to eight weeks. Weekend breaks allow normal cells Shorter periods of radiation therapy may be used to relieve symptoms. Treatments are usually given five days a week for six to seven weeks. If the goal of treatment is palliative (to control symptoms), treatment will last 2 to 3 weeks.
Using many small doses (fractions) for daily radiation, rather than a few large doses, helps protect healthy cells in the treatment area. Stopping treatment on weekends allows normal cells to recover. This allows the doctor to administer a large dose of radiation to the cancer and limits the effects on nearby tissues. Unlike photons, which pass through the body and expose tissues to radiation before and after hitting the tumor, protons only travel a certain distance, so the tissues behind the tumor are exposed to very little radiation.
For example, radiation therapy may last only a few weeks (or less) when used to relieve symptoms, because the overall dose of radiation needed is lower. If the cancer returns to the same area of the breast, you may or may not be able to receive a limited amount of additional radiation therapy in that same area. The American Cancer Society offers programs and services to help you during and after cancer treatment. A newer type of radiation therapy, called proton therapy or proton beam therapy, uses particles called protons instead of x-rays to treat cancer.
During radiation therapy, your radiation oncologist and nurse will see you regularly to track your progress, assess if you are having any side effects, recommend treatments for those side effects (such as medications), and address any concerns you may have. You may have different side effects depending on the type of cancer you have and where in your body radiation therapy is being given. Because of the potential conflict between the goal of radiation therapy (producing free radicals) and the goal of antioxidants (neutralizing free radicals), it makes sense to stop taking any antioxidant supplements during radiation therapy. Most patients drive their cars to the UC Davis Comprehensive Cancer Center and free parking is provided during the actual radiation treatment period.
Three-dimensional conformal radiation therapy (3D-CRT) delivers beams of radiation from different directions designed to match the shape of the tumor. Your radiation oncologist may tell you to avoid taking certain antioxidant vitamin supplements, such as vitamins C, A, D, and E, while receiving radiation therapy. The number of radiation treatments you will need depends on the size, location and type of cancer you have, the intention of treatment, your general health, and other medical treatments you may receive. Free radicals in the environment can damage all cells, but in the case of radiation therapy, they focus on cancer cells.