It is our hope to provide essential information for both the people living with cancer and their loved ones who are exploring radiation therapy as a treatment option. Radiation, alone or in combination with other cancer therapies, can be used to successfully treat many different types of cancer. Learning that you have cancer can bring on a flood of feelings and concerns. Searching for information about the disease and the ways to treat it can be overwhelming and confusing. As you prepare for treatment, it may help to learn as much as possible about what you may experience.
RADIATION THERAPY AND CANCER
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.
HOW DOES RADIATION THERAPY WORK?
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.
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 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 Brach therapy, involves placing radioactive sources (for example, radioactive seeds) inside your body.
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 are 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, 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.
1) 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.
2) 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.
Did You Know? Before you receive radiation therapy, your radiation oncologist, dosimetrist and medical physicist work together using sophisticated computer software to calculate the best treatment for your body. This treatment planning ensures that the tumor site receives the maximum amount of radiation while minimizing exposure to healthy tissue and organs.
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 oncologists 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.
BEFORE TREATMENT
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. After reviewing your medical tests, including CT scans, MRI scans and PET scans, and completing a through examination, your radiation oncologist will discuss with you the potential benefits and risks of radiation therapy and answer your questions.
SIMULATION
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.
TREATMENT PLANNING
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 form you 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 everyday.
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 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. FOLLOW UP
After treatment is completed, follow-up appointments will be scheduled so that your radiation oncoligist can make sure your recovery is proceeding normally and can continue to monitor your health status. Your radiation oncoligist 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 oncoligist 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. |
