How does radiation therapy work?
Radiation therapy, or radiotherapy, is a treatment in which a machine, usually a linear accelerator, uses X-rays to deliver high energy beams that are precisely aimed at the tumor site in order to destroy cancer cells and shrink tumors. Sometimes, radiation can be administered through the implantation of sources internally within the body.
How is radiation therapy different from chemotherapy?
Radiation therapy is localized radiation aimed at a tumor site; only the area that the beam penetrates will be affected. Chemotherapy is a chemical agent that is administered into your blood stream or given orally. It is systemic, meaning that your whole body may be affected by the agents administered.
Will my hair fall out?
Since radiation therapy is “localized” only the area that we are treating is affected. If we treat your head, your hair may fall out where the beam is aimed. If we are treating an area away from your head you will not experience any hair loss.
Why do I need radiotherapy?
Your doctor may prescribe radiation to cure cancer, to control the growth of the cancer or to relieve symptoms, such as pain. Radiotherapy 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:
- Destroy tumors that have not spread to other parts of your body.
- Reduce the risk that cancer will return after you undergo surgery or chemotherapy by killing small amounts of cancer that might remain.
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:
- Shrink tumors that are interfering with your quality of life, such as a lung tumor that is causing shortness of breath.
- Relieve pain by reducing the size of your tumor.
It is important for you to discuss the goal of your treatment with your radiation oncologist.
What are the different kinds of radiation?
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
What is External Beam Radiation Therapy?
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.
What is three-dimensional conformal radiation therapy (3D-CRT)
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.
What is intensity modulated radiation therapy (IMRT)?
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.
What is proton beam therapy?
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.
What is neutron beam therapy?
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.
What is stereotactic radiotherapy?
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.
What is image-guided radiation therapy (IGRT)?
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 the ability 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.
What is brachytherapy?
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.
How does radiation work in combination with other treatments including surgery or medications including chemotherapy, hormonal therapy and/or biologic therapy?
Cancer doctors usually treat cancer with radiation therapy, surgery or medications including chemotherapy, hormonal therapy and/or biologic therapy, either alone or in combination. 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. Sometimes radiation is done before or after surgery to help sterilize cancer cells that might be hard to eradicate with resection. Chemotherapy or hormonal therapy is sometimes given with radiation therapy as a “sensitizer” to make the cancer cell more susceptible to radiation killing.
What are additional treatment options?
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.
Novel targeted therapies
Cancer doctors now know much more about how cancer cell’s 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.
Intraoperative radiation therapy
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—but is always administered at the time of surgery.
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. Over the last decade, a whole arsenal of immunotherapy drugs has been developed to heighten your immune system to fight cancer.
Am I radioactive after my treatment?
No, unless you have received radioisotope therapy.
How will I feel after treatment?
Many patients don’t notice any change in the way they feel during the course of treatment. Patients, for the most part, can still drive, work and go about their daily lives during treatment. Radiation is cumulative, so over time some people may experience fatigue. Other side effects vary depending on the disease and treatment site. All potential side effects are reviewed prior to treatment.
Can I still go to work and exercise like I usually do?
Yes, continue your normal activity unless otherwise directed.
How long is each treatment?
Each day you come for treatment, please plan on being in the department for approximately 30 minutes. We allot 15 minutes for each patient’s treatment. The actual time the machine is on varies for each patient, and it is usually less than two minutes total of “beam on” time.
What can I eat?
Unless the physician and nurse give you a specialized diet at the time of your consultation, continue to follow a normal diet. Your health, including your weight, is monitored on a weekly basis during your treatment and if your diet needs to be changed or supplemented a plan will be provided.
Are there any alternative or complementary medicines can take to help the radiation work? What about high-dose vitamin supplements?
In general, the role of alternative or complementary medicines have not been well-established when used in combination with radiation. Due to harmful interactions that could possibly arise, we generally do not recommend taking any of these during treatment. If you are already on alternative medicines, we do recommend discussing these with your physician. Regarding vitamins, it is generally felt that a daily multi-vitamin is more than sufficient for patients who are ingesting a normal regular well-balanced diet.
Why do I have to come every day?
The effects of radiation to the tumor are cumulative and more effective when given over time. This also decreases the potential and severity of side effects.
Is Radiation Therapy Safe?
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.
What happens before, during and after treatment?
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.
What happens behind the scenes after my simulation?
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.
Will I feel any pain during the actual 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.
Why do I need to come in every day for external-beam radiation treatment? Why can’t this be delivered in one treatment?
Although there are some situations where radiation can be delivered in one treatment, most patients have their radiation delivered over the course of several weeks. While the radiation therapy team carefully aims the radiation in order to reduce the dose to the normal tissue surrounding the tumor, radiation will still 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.
What happens if I miss a treatment?
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.
How often will I see the doctor during treatment?
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.
How do I know if the radiation therapy is working during treatment?
Your radiation oncologist monitors your daily treatment and may alter your radiation dose based on observations. Also, your doctor may order blood tests, X-rays and other tests to see how your body is responding to treatment. Sometimes, low-resolution CT scans can be obtained during treatment to visualize the cancer. 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. 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.
What happens after treatment?
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.
Are there any side effects?
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 affects you may experience. Talk with them about any side affects 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.
How Should I Care for Myself During Radiation Therapy?
- Get plenty of rest. Many patients experience fatigue during radiation therapy, so it is important to make sure you are well rested. If possible, ask friends and family to help out during treatment, by running errands and preparing meals. This will help you get the rest you need to focus on fighting your cancer.
- Follow doctor's orders. In many cases, your doctor will ask you to call if you develop a fever of 101° or higher. Be sure to read your instructions as far as caring for yourself during treatment.
- Eat a balanced, nutritious diet. A nutritionist, nurse or doctor may work with you to make sure you are eating the right foods to get the vitamins and minerals you need. With certain types of radiation, you may need to change your diet to minimize side effects. You should not attempt to lose weight during radiation therapy since you need more calories due to your cancer and treatment.
- Treat the skin that is exposed to radiation with extra care. The skin in the area receiving treatment may become red and sensitive, similar to getting a sunburn. Your radiation oncology nurse will review specific instructions for caring for your skin with you. Some guidelines include:
- Clean the skin daily with warm water and a mild soap recommended by your nurse.
- Avoid using any lotions, perfumes, deodorants or powders in the treatment area unless approved by your doctor or nurse. Try not to use products containing alcohol and perfumes.
- Avoid putting anything hot or cold on the treated skin. This includes heating pads and ice packs.
- Stay out of the sun. If you must spend time outdoors, wear a hat or clothing to protect your skin. After treatment, use sunscreen with an SPF of at least 15.
What Questions Should I Ask My Doctor?
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
- What type and stage of cancer do I have?
- What is the purpose of radiation treatment for my type of cancer?
- How will the radiation therapy be given? Will it be external beam or brachytherapy? What do the treatments feel like?
- For how many weeks will I receive radiation? How many treatments will I receive per week?
- What are the chances that radiation therapy will work?
- Can I participate in a clinical trial? If so, what is the trial testing? What are my benefits and risks?
- What is the chance that the cancer will spread or come back if I do not have radiation therapy?
- Will I need chemotherapy, surgery or other treatments? If so, in what order will I receive these treatments? How soon after radiation therapy can I start them?
- How should I prepare for this financially?
- What are some of the support groups I can turn to during treatment?
- If I have questions after I leave here, who can I call?
- Will radiation therapy affect my ability to have children?
- Do you take my insurance?
Questions to ask during Treatment
- How can I expect to feel during treatment and in the weeks following radiation therapy?
- Can I drive myself to and from the treatment facility?
- Will I be able to continue my normal activities?
- What side effects may occur from the radiation and how are they managed?
- Do I need a special diet during or after my treatment?
- Can I exercise?
- Can I have sex?
- Can I smoke or drink alcohol?
- Will side effects change my appearance? If so, will the changes be permanent or temporary? If temporary, how long will they last?
- Is it safe to take vitamins during treatment?
Questions to ask After Treatment Ends
- How and when will you know if I am cured of cancer?
- What are the chances that the cancer will come back?
- How soon can I go back to my regular activities? Work? Sexual activity? Aerobic exercise?
- How often do I need to return for checkups?