If your cancer can be treated with radiation, you will be referred to a radiation oncologist — a doctor who specializes in treating patients with radiation therapy. Your radiation oncologist will work with your primary doctor and other cancer specialists, such as surgeons and medical oncologists, to oversee your care. He or she will discuss the details of your cancer with you, the role of radiation therapy in your overall treatment plan and what to expect from your treatment.
Radiation therapy, or radiotherapy, is the use of various forms of radiation to safely and effectively treat cancer and other diseases. Radiation oncologists may use radiation to cure cancer, to control the growth of the cancer or to relieve symptoms, such as pain. Radiation therapy works by damaging cells. Normal cells are able to repair themselves, whereas cancer cells cannot. New techniques also allow doctors to better target the radiation to protect healthy cells.
Sometimes radiation therapy is the only treatment a patient needs. At other times, it is only one part of a patient’s treatment. For example, prostate and larynx cancer are often treated with radiotherapy alone, while a woman with breast cancer may be treated with surgery, radiation therapy and chemotherapy.
Radiation may also be used to make your primary treatment more effective. For example, you can be treated with radiation therapy before surgery to help shrink the cancer and allow less extensive surgery than would otherwise be needed; or you may be treated with radiation after surgery to destroy small amounts of cancer that may have been left behind. A radiation oncologist may choose to use radiation therapy in a number of different ways. Sometimes the goal is to cure the cancer. In this case, radiation therapy may be used to:
Sometimes, the overall goal is to slow down the cancer as much as possible. In other cases, the goal is to reduce the symptoms caused by growing tumors and to improve your quality of life. When radiation therapy is administered for this purpose, it is called palliative care or palliation. In this instance, radiation may be used to:
It is important for you to discuss the goal of your treatment with your radiation oncologist.
The goal of radiation therapy is to get enough radiation into the body to kill the cancer cells while preventing damage to healthy tissue. There are several ways to do this. Depending on the location, size and type of cancer, you may receive one or a combination of techniques. Your treatment team will help you to decide which treatments are best for you. Radiation therapy can be delivered in two ways, externally and internally. During external beam radiation therapy, the radiation oncology team uses a machine to direct high-energy X-rays at the cancer. Internal radiation therapy, or brachytherapy, involves placing radioactive sources (for example, radioactive seeds) inside your body.
During external beam radiation therapy, a beam of radiation is directed through the skin to the cancer and the immediate surrounding area in order to destroy the main tumor and any nearby cancer cells. To minimize side effects, the treatments are typically given five days a week, Monday through Friday, for a number of weeks. This allows doctors to get enough radiation into the body to kill the cancer while giving healthy cells time each day to recover.
The radiation beam is usually generated by a machine called a linear accelerator. The linear accelerator, or linac, is capable of producing high-energy X-rays and electrons for the treatment of your cancer. Using high-tech treatment planning software, your treatment team controls the size and shape of the beam, as well as how it is directed at your body, to effectively treat your tumor while sparing the surrounding normal tissue. Several special types of external beam therapy are discussed in the next sections. These are used for specific types of cancer, and your radiation oncologist will recommend one of these treatments if he or she believes it will help you.
Tumors are not regular - they come in different shapes and sizes. Three-dimensional conformal radiation therapy, or 3D-CRT, uses computers and special imaging techniques to show the size, shape and location of the tumor. Computer assisted tomography (CT or CAT scans), magnetic resonance imaging (MR or MRI scans) and/or positron emission tomography (PET scans) are used to create detailed, three-dimensional representations of the tumor and surrounding organs. Your radiation oncologist can then precisely tailor the radiation beams to the size and shape of your tumor with multileaf collimators (see picture, right) or custom fabricated field shaping blocks. Because the radiation beams are very precisely directed, nearby normal tissue receives less radiation and is able to heal quickly.
Intensity modulated radiation therapy, or IMRT, is a specialized form of 3D-CRT that allows radiation to be more exactly shaped to fit the tumor. With IMRT, the radiation beam can be broken up into many "beamlets," and the intensity of each beamlet can be adjusted individually. Using IMRT, it may be possible to further limit the amount of radiation that is received by healthy tissue near the tumor. In some situations, this may also allow a higher dose of radiation to be delivered to the tumor, potentially increasing the chance of a cure.
Proton beam therapy is a form of external beam radiation treatment that uses protons rather than X-rays to treat certain types of cancer and other diseases. The physical characteristics of the proton therapy beam allow doctors to more effectively reduce the radiation dose to nearby healthy tissue. Proton therapy is available at only a few specialized centers in the country.
Like proton therapy, neutron beam therapy is a specialized form of external beam radiation therapy. It is often used to treat certain tumors that are radioresistant, meaning that they are very difficult to kill using conventional X-ray radiation therapy. Neutrons have a greater biologic impact on cells than other types of radiation. Used carefully, this added impact can be an advantage in certain situations. Neutron therapy is available at only a few specialized centers.
Stereotactic radiotherapy is a technique that allows your radiation oncologist to precisely focus beams of radiation to destroy certain types of tumors. Since the beam is so precise, your radiation oncologist may be able to spare more healthy tissue. This additional precision is achieved by using a very secure immobilization, such as a head frame used in the treatment of brain tumors. Stereotactic radiotherapy is frequently given in a single dose (sometimes called radiosurgery) although certain situations may require more than one dose. In addition to treating some cancers, radiosurgery can also be used to treat malformations in the brain's blood vessels and certain noncancerous (benign) neurologic conditions. Sometimes a high dose of stereotactic radiotherapy can be focused upon a tumor outside the brain and given in a few treatments (typically three to eight). This form of treatment is called stereotactic body radiation therapy.
Radiation oncologists use image-guided radiation therapy, or IGRT, to help better deliver the radiation to the cancer since tumors can move between treatments due to differences in organ filling or movements while breathing. IGRT involves conformal radiation treatment guided by imaging, such as CT, ultrasound or X-rays, taken in the treatment room just before the patient is given the radiation treatment. All patients first undergo a CT scan as part of the planning process. The imaging information from the CT scan is then transmitted to a computer in the treatment room to allow doctors to compare the earlier image with the images taken just before treatment. During IGRT, doctors compare these images to see if the treatment needs to be adjusted. This allows doctors to better target the cancer while avoiding nearby healthy tissue. In some cases, doctors will implant a tiny marker in or near the tumor to pinpoint it for IGRT.
Also known as internal radiation, brachytherapy involves placing radioactive material into a tumor or its surrounding tissue. Because the radiation sources are placed so close to the tumor, your radiation oncologist can deliver a large dose of radiation directly to the cancer cells. The radioactive sources used in brachytherapy, such as thin wires, ribbons, capsules or seeds, come in small sealed containers. These sources may be implanted permanently or temporarily. A permanent implant remains in the body after the sources are no longer radioactive. Other radioactive sources are placed temporarily inside the body and are removed after the right amount of radiation has been delivered.
Certain cancers may be treated by swallowing radioactive pills or receiving radioactive fluids in the vein (intravenous). This type of treatment is called systemic radiation therapy because the medicine goes to the entire body. For example, radioactive iodine (I-131) capsules are given to treat some types of thyroid cancer. Another example is the use of intravenous radioactive material to treat pain due to cancer that has spread to the bone. Radiolabeled antibodies are monoclonal antibodies with radioactive particles attached. These antibodies are designed to attach themselves directly to the cancer cell and damage it with small amounts of radiation.
Cancer doctors now know much more about how cancer cells function. New cancer therapies use this information to target cancer cell functions and stop them. Called targeted therapies, they can be more specific in stopping cancer cells from growing and may make other treatments work better. For example, some medicines work to prevent cancers from growing by preventing the growth of new blood vessels that would nourish the cancer. Other targeted therapies work more directly on cancer cells by blocking the action of molecules on the surface of cancer cells called growth factors.
Any drug that can make tumor cells more sensitive to radiation is called a radiosensitizer. Combining radiation with radiosensitizers may allow doctors to kill more tumor cells. Some types of chemotherapy and some novel targeted therapies can act as radiosensitizers.
Some medicines called radioprotectors can help protect healthy tissue from the effects of radiation.
Radiation therapy given during surgery is called intraoperative radiation therapy. Intraoperative radiation therapy is helpful when vital normal organs are too close to the tumor. During an operation, a surgeon temporarily moves the normal organs out of the way so radiation can be applied directly to the tumor. This allows your radiation oncologist to avoid exposing those organs to radiation. Intraoperative radiation can be given as external beam therapy or as brachytherapy.
Medicines prescribed by a medical oncologist that can kill cancer cells directly are called chemotherapy. Some are given in pill form, and some are given by injection. Chemotherapy can also be considered a type of systemic therapy, because medicines go through the bloodstream to the entire body.
Some treatments are designed to help your own body's immune system fight the cancer, similar to how your body fights off infections.
A team of highly trained medical professionals will be involved in your care during radiation therapy. This team is led by a radiation oncologist, a doctor who specializes in using radiation to treat cancer.
Radiation oncologists are the doctors who will oversee your radiation therapy treatments. These physicians work with the other members of the radiation therapy team to develop and prescribe your treatment plan and make sure that each treatment is given accurately. Your radiation oncologist will also track your progress and adjust the treatment as necessary to make sure you receive the best care. Radiation oncologists help identify and treat any side effects that may occur due to radiation therapy. They work closely with other cancer doctors, including medical oncologists and surgeons, and all members of the radiation oncology team.
Radiation oncologists have completed at least four years of college, four years of medical school, one year of general medical training and four years of residency (specialty) training in radiation oncology. They have extensive training in cancer medicine and the safe use of radiation to treat disease. If they pass a special examination, they are certified by the American Board of Radiology. You should ask if your doctor is board certified.
Medical physicists work directly with the radiation oncologist during treatment planning and delivery. They oversee the work of the dosimetrist and help ensure that complex treatments are properly tailored for each patient. Medical physicists develop and direct quality control programs for equipment and procedures. They also make sure the equipment works properly by taking precise measurements of the radiation beam and performing other safety tests on a regular basis.
Dosimetrists work with the radiation oncologist and medical physicist to carefully calculate the dose of radiation to make sure the tumor gets enough radiation. Using computers, they develop a treatment plan that can best destroy the tumor while sparing the healthy tissue.
Radiation therapists work with radiation oncologists to give the daily radiation treatment under the doctor's prescription and supervision. They maintain daily records and regularly check the treatment machines to make sure they are working properly.
Radiation oncology nurses work with every member of the treatment team to care for you and your family before, during and after treatment. They will explain the possible side effects you may experience and will describe how you can manage them. They will assess how you are doing throughout treatment and will help you cope with the changes you are experiencing. If they pass a special exam, they are certified by the Oncology Nursing Exam as an Oncology Certified Nurse.
You may work with a number of other healthcare professionals while undergoing radiation therapy. These specialists ensure that all of your physical and psychological needs are met during your treatment.
Social workers are available to provide a variety of support services to you and your family. They can provide counseling to help you and your family cope with the diagnosis of cancer and with your treatment. They may also help arrange for home healthcare and other services.
Dietitians can work with you to help you eat right during your treatments. They can help you modify your eating plan if treatment is affecting your appetite and what you can eat, and can provide recipes, menu suggestions and information on helping manage some treatment side effects from a dietary standpoint. Any dietary issues and questions you may have regarding supplements and claims you may read about can also be addressed at time of consult or during treatment
Physical therapists use exercises to help your body function properly while you are undergoing treatment. These exercises can help manage side effects, alleviate pain and keep you healthy.
Dentists may be involved if you are receiving radiation for oral or head and neck cancers. They will help prevent the radiation from damaging the healthy areas of your mouth, caring for teeth, gums and other tissues in the mouth, and may recommend preventive dental work before radiation. They will also help manage oral side effects of cancer therapy, such as dry mouth.
Some patients are concerned about the safety of radiation therapy. Radiation has been used successfully to treat patients for more than 100 years. In that time, many advances have been made to ensure that radiation therapy is safe and effective.
Before you begin receiving radiation therapy, your radiation oncology team will carefully tailor your plan to make sure that you receive safe and accurate treatment. Treatment will be carefully planned to focus on the cancer while avoiding healthy organs in the area. Throughout your treatment, members of your team check and re-check your plan. Special computers are also used to monitor and double-check the treatment machines to make sure that the proper treatment is given. If you undergo external beam radiation therapy, you will not be radioactive after treatment ends because the radiation does not stay in your body. However, if you undergo brachytherapy, tiny radioactive sources will be implanted inside your body, in the tumor or in the tissue surrounding the tumor, either temporarily or permanently. Your radiation oncologist will explain any special precautions that you or your family and friends may need to take.
Some patients worry that radiation therapy will cause cancer years after treatment. While this is a very small risk, it is most important to cure the cancer now. Talk with your radiation oncologist or radiation oncology nurse about any fears you may have. Like all therapies, radiation can cause side effects. See page 17 for more information.
Once the diagnosis has been made, you will probably talk with your primary care physician along with several cancer specialists, such as a surgeon, a medical oncologist and a radiation oncologist, to discuss your treatment choices. These specialists will work together to help recommend the best treatment for you. In some cases, your cancer will need to be treated by using more than one type of treatment. For example, if you have breast cancer, you might have surgery to remove the tumor (by a surgeon), then have radiation therapy to destroy any remaining cancer cells in or near your breast (by a radiation oncologist). You also might receive chemotherapy (by a medical oncologist) to destroy cancer cells that have traveled to other parts of the body.
Meeting With a Radiation Oncologist
If you are considering radiation therapy, you must first meet with a radiation oncologist to see if radiation therapy is right for you. During your first visit, your doctor will evaluate your need for radiation therapy and its likely results. This includes reviewing your current medical problems, past medical history, past surgical history, family history, medications, allergies and lifestyle. The doctor will also perform a physical exam to assess the extent of your disease and judge your general physical condition. You may also be seen by a medical student, a resident (radiation oncologist in training), a nurse practitioner, a physician's assistant or a nurse. After reviewing your medical tests, including CT scans, MRI scans and PET scans, and completing a thorough examination, your radiation oncologist will discuss with you the potential benefits and risks of radiation therapy and answer your questions. For a list of questions that you may want to ask, please see the section 'What Questions Should I Ask My Doctor?' on page 20.
To be most effective, radiation therapy must be aimed precisely at the same target or targets each and every time treatment is given. The process of measuring your body and marking your skin to help your team direct the beams of radiation safely and exactly to their intended locations is called simulation. During simulation, your radiation oncologist and radiation therapist place you on the simulation machine in the exact position you will be in during the actual treatment. Your radiation therapist, under your doctor's supervision, then marks the area to be treated directly on your skin or on immobilization devices. Immobilization devices are molds, casts, headrests or other devices that help you remain in the same position during the entire treatment. The radiation therapist marks your skin and/or the immobilization devices either with a bright, temporary paint or a set of small, permanent tattoos.
Your radiation oncologist may request that special blocks or shields be made for you. These blocks or shields are put in the external beam therapy machine before each of your treatments and are used to shape the radiation to your tumor and keep the rays from hitting normal tissue. Multileaf collimators may also be used to shape the beam and achieve safe delivery of your radiation treatment.
Once you have finished with the simulation, your radiation oncologist and other members of the treatment team review the information they obtained during simulation along with your previous medical tests to develop a treatment plan. Often, a special treatment planning CT scan is done to help with the simulation and treatment planning. This CT scan is in addition to your diagnostic CT scan. Frequently, sophisticated treatment-planning computer software is used to help design the best possible treatment plan. After reviewing all of this information, your doctor will write a prescription that outlines exactly how much radiation you will receive and to what parts of your body.
External Beam Radiation Therapy Treatments
When you undergo external beam radiation therapy treatment, each session is painless, just like getting an X-ray. The radiation is directed at your tumor from a machine located away from your body, usually a linear accelerator. External beam radiation is noninvasive, unlike surgery which is an invasive process. One of the benefits of radiation therapy is that it is usually given as a series of outpatient treatments (meaning you don't have to stay in the hospital). You may not need to miss work or experience the type of recuperation period that may follow other treatments.
Treatments are usually scheduled five days a week, Monday through Friday, and continue for one to 10 weeks. The number of radiation treatments you will need depends on the size, location and type of cancer you have, the intent of the treatment, your general health and other medical treatments you may be receiving. The radiation therapist will give you your external beam treatment following your radiation oncologist's instructions. It will take five to 15 minutes for you to be positioned for treatment and for the equipment to be set up. If an immobilization device was made during simulation, it will be used during every treatment to make sure that you are in the exact same position every day.
Once you are positioned correctly, the therapist will leave the room and go into the control room next door to closely monitor you on a television screen while giving the radiation. There is a microphone in the treatment room so you can always talk with the therapist if you have any concerns. The machine can be stopped at any time if you are feeling sick or uncomfortable. The radiation therapist may move the treatment machine and treatment table to target the radiation beam to the exact area of the tumor. The machine might make noises during treatment that sound like clicking, knocking or whirring, but the radiation therapist is in complete control of the machine at all times.
The radiation therapy team carefully aims the radiation in order to reduce the dose to the normal tissue surrounding the tumor. Still, radiation will affect some healthy cells. Time between daily treatments allows your healthy cells to repair much of the radiation effect, while cancer cells are not as likely to survive the changes.
Sometimes a course of treatment is interrupted for a day or more. This may happen if you develop side effects that require a break in treatment. These missed treatments may be made up by adding treatments at the end. Try to arrive on time and not miss any of your appointments. Time spent in the treatment room may vary depending on the type of radiation, but it generally ranges from 10 to 40 minutes. Most patients are treated on an outpatient basis, and many can continue with normal daily activities.
Your radiation oncologist monitors your daily treatment and may alter your radiation dose based on these observations. Also, your doctor may order blood tests, X-rays and other tests to see how your body is responding to treatment. If the tumor shrinks significantly, another simulation may be required. This allows your radiation oncologist to change the treatment to destroy the rest of the tumor and spare even more normal tissue.
Weekly Status Checks
During radiation therapy, your radiation oncologist and nurse will see you regularly to follow your progress, evaluate whether you are having any side effects, recommend treatments for those side effects (such as medication), and address any concerns you may have. As treatment progresses, your doctor may make changes in the schedule or treatment plan depending on your response or reaction to the therapy. Your radiation therapy team may gather on a regular basis with other healthcare professionals to review your case to ensure your treatment is proceeding as planned. During these sessions, all the members of the team discuss your progress as well as any concerns.
Weekly Beam Films
During your course of treatment, correct positions of the treatment beams will be regularly verified with images made using the treatment beam itself. These images (called port films, beam films or portal verification) represent an important quality assurance check, but do not evaluate the tumor itself.
Brachytherapy is the placement of radioactive sources in or just next to a tumor. The word brachytherapy comes from the Greek "brachy" meaning short distance. During brachytherapy, the radioactive sources may be left in place permanently or only temporarily, depending upon your cancer. To position the sources accurately, special catheters or applicators are used.
There are two main types of brachytherapy - intracavitary treatment and interstitial treatment. With intracavitary treatment, the radioactive sources are put into a space near where the tumor is located, such as the cervix, the vagina or the windpipe. With interstitial treatment, the radioactive sources are put directly into the tissues, such as the prostate.
Sometimes these procedures require anesthesia and a brief stay in the hospital. Patients with permanent implants may have a few restrictions at first and then can quickly return to their normal activities. Temporary implants are left inside of your body for several hours or days. While the sources are in place, you will stay in a private room. Doctors, nurses and other medical staff will continue to take care of you, but they will take special precautions to limit their exposure to radiation. Devices called high-dose-rate remote afterloading machines allow radiation oncologists to complete brachytherapy quickly, in about 10 to 20 minutes. Powerful radioactive sources travel through small tubes called catheters to the tumor for the amount of time prescribed by your radiation oncologist. You may be able to go home shortly after the procedure. Depending on the area treated, you may receive several treatments over a number of days or weeks.
Most patients feel little discomfort during brachytherapy. If the radioactive source is held in place with an applicator, you may feel discomfort from the applicator. There are medications that can relieve this discomfort. If you feel weak or queasy from the anesthesia, your radiation oncologist can give you medication to make you feel better. Depending on the type of brachytherapy you received, you may need to take some precautions after you leave your treatment, particularly if you plan to be around young children or pregnant women. Ask your radiation oncologist or radiation oncology nurse about anything special you should know.
After treatment is completed, follow-up appointments will be scheduled so that your radiation oncologist can make sure your recovery is proceeding normally and can continue to monitor your health status. Your radiation oncologist may also order additional diagnostic tests. Reports on your treatment may also be sent to the other doctors helping treat your cancer. As time goes by, the number of times you need to visit your radiation oncologist will decrease. However, you should know that your radiation oncology team will always be available should you need to speak to someone about your treatment.
Radiation therapy is usually well tolerated and many patients are able to continue their normal routines. However, some patients may eventually develop painful side effects. Be sure to talk to a member of your radiation oncology treatment team about any problems or discomfort you may have. Many of the side effects of radiation therapy are only in the area being treated. For example, a breast cancer patient may notice skin irritation, like a mild to moderate sunburn, while a patient with cancer in the mouth may have soreness when swallowing. Some patients who are having their midsection treated may report feeling sick to their stomach. These side effects are usually temporary and can be treated by your doctor or other members of the treatment team.
Side effects usually begin by the second or third week of treatment, and they may last for several weeks after the final radiation treatment. In rare instances, serious side effects develop after radiation therapy is finished. Your radiation oncologist and radiation oncology nurse are the best people to advise you about the side effects you may experience. Talk with them about any side effects you are having. They can give you information about how to manage them and may prescribe medicines or changes in your eating habits to help relieve your discomfort.
The side effect most often reported by patients receiving radiation is fatigue. The fatigue patients experience is usually not severe, and patients may be able to continue all or some of their normal daily activities with a reduced schedule. However, treating cancer often requires considerable mental and physical effort. Whenever possible, try to take time during your treatment to rest and relax.
Many patients are concerned that radiation therapy will cause another cancer. In fact, the risk of developing a second tumor because of radiation therapy is very low. For many patients, radiation therapy can cure your cancer. This benefit far outweighs the very small risk that the treatment could cause a later cancer. If you smoke, the most important thing you can do to reduce your risk of a second cancer is to quit smoking.
Cancer specialists regularly conduct studies to test new treatments. These studies are called clinical trials. Clinical trials are available through cancer doctors everywhere- not just in major cities or in large hospitals.
Some clinical studies try to determine if a therapeutic approach is safe and potentially effective. Many large clinical trials compare the more commonly used treatment with a treatment that cancer experts think might be better. Patients who participate in clinical trials help doctors and future cancer patients find out whether a promising treatment is safe and effective. All patients who participate in clinical trials are carefully monitored to make sure they are getting quality care. It is important to remember that clinical trials are completely voluntary. Patients can leave a trial at any time. Clinical trials testing new treatments are carried out in phases:
Only you can make the decision about whether or not to participate in a clinical trial. Before making your decision, it is important to learn as much as possible about your cancer and the clinical trials that may be available to you. Your radiation oncologist can answer many of your questions if you are considering taking part in a trial or contact the National Cancer Institute at 1-800-4-CANCER or www.cancer.gov.
Coping with a diagnosis of cancer and researching the various treatment options can be a stressful experience. To assist you in this process, below is a list of questions you may want to ask your radiation oncologist if you are considering radiation therapy.
Questions to ask before treatment
Questions to ask during Treatment
Questions to ask After Treatment Ends