Radiation therapy may vary somewhat among different doctors, hospitals, and treatment centers. Therefore, your treatment or the advice of your the radiation oncologist may be different from what you read here. Be sure to ask questions and discuss your concerns with your doctor, nurse, or radiation therapist. Ask whether they have any additional written information that might help you.
Radiation therapy (sometimes called radiotherapy, x-ray therapy, or irradiation) is the treatment of disease using penetrating beams of high energy waves or streams of particles called radiation. Many years ago doctors learned how to use this energy to "see" inside the body and find disease. You've probably seen a chest x-ray or x-ray pictures of your teeth or your bones. At high doses (many times those used for x-ray exams) radiation is used to treat cancer and other illnesses. The radiation used for cancer treatment comes from special machines or from radioactive substances. Radiation therapy equipment aims specific amounts of the radiation at tumors or areas of the body where there is disease.
Radiation in high doses kills cells or keeps them from growing and dividing. Because cancer cells grow and divide more rapidly than most of the normal cells around them, radiation therapy can successfully treat many kinds of cancer. Normal cells are also affected by radiation but, unlike cancer cells, most of them recover from the effects of radiation. To protect normal cells, doctors carefully limit the doses of radiation and spread the treatment out over time. They also shield as much normal tissue as possible while they aim the radiation at the site of the cancer.
The goal of radiation therapy is to kill the cancer cells with as little risk as possible to normal cells. Radiation therapy can be used to treat many kinds of cancer in almost any part of the body. In fact, more than half of all people with cancer are treated with some form of radiation. For many cancer patients, radiation is the only kind of treatment they need. Thousands of people who have had radiation therapy alone or in combination with other types of cancer treatment are free of cancer. Radiation treatment, like surgery, is a local treatment it affects the cancer cells only in a specific area of the body. Sometimes doctors add radiation therapy to treatments that reach all parts of the body (systemic treatment) such as chemotherapy, or biological therapy to improve treatment results. You may hear your doctor use the term, adjuvant therapy, for a treatment that is added to, and given after, the primary therapy. Radiation therapy is often used with surgery to treat cancer. Doctors may use radiation before surgery to shrink a tumor. This makes it easier to remove the cancerous tissue and may allow the surgeon to perform less radical surgery. Radiation therapy may be used after surgery to stop the growth of cancer cells that may remain. Your doctor may choose to use radiation therapy and surgery at the same time. In some cases, instead of surgery, doctors use radiation along with anticancer drugs (chemotherapy) to destroy the cancer. Radiation may be given before, during, or after chemotherapy. Doctors carefully tailor this combination treatment to each patient's needs depending on the type of cancer, its location, and its size. The purpose of radiation treatment before or during chemotherapy is to make the tumor smaller and thus improve the effectiveness of the anticancer drugs. Doctors sometimes recommend that a patient complete chemotherapy and then have radiation treatment to kill any cancer cells that might remain. When curing the cancer is not possible, radiation therapy can be used to shrink tumors and reduce pressure, pain, and other symptoms of cancer. This is called palliative care or palliation. Many cancer patients find that they have a better quality of life when radiation is used for this purpose.
The brief high doses of radiation that damage or destroy cancer cells can also injure or kill normal cells. These effects of radiation on normal cells cause treatment side effects. Most side effects of radiation treatment are well known and, with the help of your doctor and nurse, easily treated. The side effects of radiation therapy and what to do about them are discussed in the Managing Side Effects section. The risk of side effects is usually less than the benefit of killing cancer cells. Your doctor will not advise you to have any treatment unless the benefits - control of disease and relief from symptoms - are greater than the known risks.
Radiation therapy can be given in one of two ways: external or internal. Some patients have both, one after the other. Most people who receive radiation therapy for cancer have external radiation . It is usually given during outpatient visits to a hospital or treatment center. In external radiation therapy, a machine directs the high-energy rays at the cancer and a small margin of normal tissue surrounding it. The various machines used for external radiation work in slightly different ways. Some are better for treating cancers near the skin surface; others work best on cancers deeper in the body. The most common type of machine used for radiation therapy is called a linear accelerator . Some radiation machines use a variety of radioactive substances (such as cobalt-60, for example) as the source of high-energy rays. Your doctor decides which type of radiation therapy machine is best for you. You will find more information about external radiation in the next chapter. When internal radiation therapy is used, the radiation source is placed inside the body. This method of radiation treatment is called brachytherapy or implant therapy. The source of the radiation (such as radioactive iodine, for example) sealed in a small holder is called an implant . Implants may be thin wires, plastic tubes (catheters), capsules, or seeds. An implant may be placed directly into a tumor or inserted into a body cavity. Sometimes, after a tumor has been removed by surgery, the implant is placed in the 'tumor bed' (the area from which the tumor was removed) to kill any tumor cells that may remain. Another type of internal radiation therapy uses unsealed radioactive materials which may be taken by mouth or injected into the body. If you have this type of treatment, you may need to stay in the hospital for several days. See the internal radiation therapy section for more information.
A doctor who specializes in using radiation to treat cancer - a radiation oncologist - will prescribe the type and amount of treatment that is right for you. The radiation oncologist is the person referred to as "your doctor" throughout this booklet. The radiation oncologist works closely with the other doctors and health care professionals involved in your care. This highly trained health care team may include:
Treatment of cancer with radiation can be costly. It requires very complex equipment and the services of many health care professionals. The exact cost of your radiation therapy will depend on the type and number of treatments you need. Most health insurance policies, including Part B of Medicare, cover charges for radiation therapy. It's a good idea to talk with your doctor's office staff or the hospital business office about your policy and how expected costs will be paid. In some states, the Medicaid program may help you pay for treatments. You can find out from the office that handles social services in your city or county whether you are eligible for Medicaid and whether your radiation therapy is a covered expense. If you need financial aid, contact the hospital Social Work office or the National Cancer Institute's (NCI) Cancer Information Service at 1-800-4-CANCER. They may be able to direct you to sources of help. Additional sources of cancer information are described in the resources section.
The high-energy rays used for radiation therapy can come from a variety of sources. Your doctor may choose to use x-rays, an electron beam, or cobalt-60 gamma rays. Some cancer treatment centers have special equipment that produces beams of protons or neutrons for radiation therapy. The type of radiation your doctor decides to use depends on what kind of cancer you have and how far into your body the radiation should go. High-energy radiation is used to treat many types of cancer. Low-energy x-rays are used to treat some kinds of skin diseases. After a physical exam and a review of your medical history, the doctor plans your treatment. In a process called simulation, you will be asked to lie very still on an examining table while the radiation therapist uses a special x-ray machine to define your treatment port or field. This is the exact place on your body where the radiation will be aimed. Depending on the location of your cancer, you may have more than one treatment port. Simulation may also involve CT scans or other imaging studies to plan how to direct the radiation. Depending on the type of treatment you will be receiving, body molds or other devices that keep you from moving during treatment (immobilization devices) may be made at this time. They will be used each time you have treatment to be sure that you are positioned correctly. Simulation may take from a half hour to about 2 hours. The radiation therapist often will mark the treatment port on your skin with tattoos or tiny dots of colored, permanent ink. It's important that the radiation be targeted at the same area each time. If the dots appear to be fading, tell your radiation therapist who will darken them so that they can be seen easily. Once simulation has been done, your doctor will meet with the radiation physicist and the dosimetrist. Based on the results of your medical history, lab tests, x-rays, other treatments you may have had, and the location and kind of cancer you have, they will decide how much radiation is needed, what kind of machine to use to deliver it, and how many treatments you should have. After you have started the treatments, your doctor and the other members of your health care team will follow your progress by checking your response to treatment and how you are feeling at least once a week. When necessary, your doctor may revise the treatment plan by changing the radiation dose or the number and length of your remaining radiation sessions. Your nurse will be available daily to discuss your concerns and answer any questions you may have. Be sure to tell your nurse if you are having any side effects or if you notice any unusual symptoms.
For most types of cancer, radiation therapy usually is given 5 days a week for 6 or 7 weeks. When radiation is used for palliative care, the course of treatment is shorter, usually 2 to 3 weeks. The total dose of radiation and the number of treatments you need will depend on the size, location, and kind of cancer you have, your general health, and other medical treatments you may be receiving. Using many small doses of daily radiation rather than a few large doses helps protect normal body tissues in the treatment area. Weekend rest breaks allow normal cells to recover. It's very important that you have all of your scheduled treatments to get the most benefit from your therapy. Missing or delaying treatments can lessen the effectiveness of your radiation treatment.
Before each treatment, you may need to change into a hospital gown or robe. It's best to wear clothing that is easy to take off and put on again. In the treatment room, the radiation therapist will use the marks on your skin to locate the treatment area and to position you correctly. You may sit in a special chair or lie down on a treatment table. For each external radiation therapy session, you will be in the treatment room about 15 to 30 minutes, but you will be getting radiation for only about 1 to 5 minutes of that time. Receiving external radiation treatments is painless, just like having an x-ray taken. You will not hear, see, or smell the radiation. The radiation therapist may put special shields (or blocks) between the machine and certain parts of your body to help protect normal tissues and organs. There might also be plastic or plaster forms that help you stay in exactly the right place. You need to remain very still during the treatment so that the radiation reaches only the area where it's needed and the same area is treated each time. You don't have to hold your breath - just breathe normally. The radiation therapist will leave the treatment room before your treatment begins. The radiation machine is controlled from a nearby area. You will be watched on a television screen or through a window in the control room. Although you may feel alone, keep in mind that the therapist can see and hear you and even talk with you using an intercom in the treatment room. If you should feel ill or very uncomfortable during the treatment, tell your therapist at once. The machine can be stopped at any time.
The machines used for radiation treatments are very large, and they make noises as they move around your body to aim at the treatment area from different angles. Their size and motion may be frightening at first. Remember that the machines are being moved and controlled by your radiation therapist. They are checked constantly to be sure they're working right. If you have concerns about anything that happens in the treatment room, discuss these concerns with the radiation therapist.
FAQs courtesy of the National Cancer Institute