Neuro-Oncology University of Washington Medical Center

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Treatment Strategies: Radiation Therapy Radiation therapy is usually prescribed for low grade tumors (benign) that are incompletely removed and for all high grade tumors (malignant). Radiation therapy works primarily by damaging the DNA in cells, thereby preventing those cells from dividing (growing). Because tumor cells are capable of dividing, radiation therapy is given to prevent any remaining tumor cells from growing. Normal brain cells do not divide as rapidly and thus are not affected by radiation to the extent that tumor cells are affected. In addition, normal brain cells have the capacity to repair radiation damage, whereas tumor cells are less able to repair themselves. Standard external beam radiation therapy is usually administered every day (excluding weekends) for about six weeks, or for 28 to 33 treatments, depending upon the grade and location of the tumor. The dose of the radiation, the areas of the brain that are to be treated, and how the radiation will be administered are determined by the radiation oncologist. A dosimetrist works with the radiation oncologist to determine, via a computer, how the radiation treatment can deliver maximal radiation to the tumor with minimal exposure to normal cells. Radiation: What to Expect Your first appointment in radiation oncology will be spent meeting with your radiation oncologist. During this time a review of your medical history and a physical examination will be done. In addition, an explanation of radiation therapy will be given to you, including why it has been recommended for you. An explanation of any associated risks or benefits also will be reviewed. The next couple of appointments will be spent planning your radiation therapy. During these appointments a special mesh mask will be made for you. You will wear this mask during each radiation treatment to ensure that your head does not move during treatment and that your head is always kept in the same exact position from treatment to treatment. The planning sessions for your radiation are called a "simulation." Most common side effects Many individuals receiving brain radiation experience no side effects other than hair loss. Others may experience some minor side effects. When side effects do occur, they most commonly include skin irritation or redness in the area being treated, hair loss, fatigue, occasionally a small amount of fluid collection in the middle ear (behind the ear drum) and irritation of the ear canal if radiation is being delivered in this area. It is important that you do not treat skin irritation yourself. Massaging creams into the affected scalp area can cause a radiation burn. Your physician or nurse will give you a special solution or medication that you can safely apply to irritated areas. You can shampoo your scalp and hair as often as you wish, however you should use a mild, fragrance-free soap such as Ivory soap, Basis or Neutrogena shampoo. You should not scrub your scalp. In addition, you must protect your scalp and radiation treatment areas from the sun. DO NOT use sun screen on affected areas during the six week period of your radiation therapy, but rather cover your head with a hat or scarf. Hair loss in the treatment area begins two to three weeks after your initial treatment. Hair loss occurs because radiation affects cells that are dividing, which includes hair follicles. Hair regrowth patterns vary. Hair may begin to regrow anywhere from three to twelve months following radiation therapy. Hair that grows back may come back in a thinner distribution than your normal hair, and it may even return a different color or texture. In some cases, depending on radiation dose, hair regrowth does not occur. There are a variety of resources for headwraps, turbans, and wigs offered through the UWMC Volunteer Services. To contact the Volunteer Services, call (206)548-4218. At Harborview Medical Center these needs are met by the oncology and neurosurgery social workers who can be contacted by calling (206)731-8030. If you are interested in information regarding hair alternatives please tell your nurse. The American Cancer Society publishes a booklet for patients experiencing hair loss which may also be helpful. Fatigue, if it occurs, tends to be greater as the treatment progresses. For example, it may be more pronounced on Fridays (the fifth day of radiation treatment each week), and it may be more noticeable toward the end of the radiation treatment (during the fourth or fifth week). Why this fatigue occurs is not clearly understood. If you develop fatigue, taking a nap each day will help to relieve it. in some cases patients experience fatigue after the completion of radiation. Delayed fatigue may occur from one to three months after treatment and may last from four to six weeks. Fluid accumulation in your middle ear may cause you to experience a feeling of "plugged" ears and decrease your hearing in the ear that is in the radiation treatment field. This fluid accumulation is usually temporary and can result from inflammation of the middle ear. Should you develop this problem, your radiation oncologist may prescribe medication to help "dry-up" this fluid. Also, your ears will be inspected for any signs of infection which may occur with the irritation and fluid build-up in the ear. An antibiotic will be prescribed should this occur. Occasionally, depending upon what brain areas are being radiated, individuals may experience a mild nausea an hour or two after their daily radiation treatment. This can typically be managed with anti-nausea medication. Other individuals may experience a decrease in their appetite. It is important to eat nutritious, well-balanced meals during your radiation treatment. A clinical dietitian is available to advise you on nutrition concerns. If you lose weight, you may be requested to add a dietary supplement to your daily food intake. Some patients may experience a headache, which may require steroid medication. Patients often ask about taking vitamins during their treatments. A regular multivitamin is safe for you to take. However, you must not take "mega" doses of vitamins A, beta carotene, C, or E during radiation therapy (or during and within a few days before or after receiving chemotherapy drugs). This is because, theoretically, these vitamins may reverse the radiation or chemotherapeutic effects on the tumor cells. With the exception of vitamin A (which can be toxic), these vitamins may safely be taken after your radiation treatment is completed. How well your tumor has responded to the radiation treatment may not be determined for several months. This is because tumor cells may remain for a time following radiation therapy as the brain is not as efficient as other organs of the body in "cleaning-up" dead tissue. Generally, an MRI or CT scan will be done within a few weeks of the completion of your radiation therapy. This scan may still show the presence of tumor cells; what the scan cannot tell the physician is whether these are dead tumor cells or active tumor cells. The scan is useful, however, to determine if there has been tumor growth, and to provide a baseline for future scans. Long term injury from radiation is much less common than the side effects noted above. Your radiation oncologist will talk to you about these less common side effects.   Top of Page   |  Next Page