Radiation therapy uses high-energy particles or waves, such as x-rays, gamma rays, electrons, or protons to destroy or damage cancer cells. Other names for radiation therapy include radiotherapy or x-ray therapy.

Radiation therapy is one of the most common treatments for cancer. It is often part of the main treatment for some types of cancer, such as cancers of the head and neck, bladder, lung, and Hodgkin disease. Many other cancers are also treated with radiation therapy. Thousands of people become free of cancer after receiving radiation treatments, either alone or combined with other treatments such as surgery or chemotherapy.


How Does Radiation Therapy Work?

All cells, whether cancerous or healthy, grow and divide to form new cells. But cancer cells grow and divide more quickly than many of the normal cells around them.

Radiation therapy uses special equipment to deliver high doses of radiation to cancerous cells, killing or damaging them so they cannot grow or spread. It works by breaking a strand of the DNA molecule inside the cancer cell, which prevents the cell from growing and dividing. Although some normal cells may be affected by radiation, most recover fully from the effects of the treatment.

Unlike chemotherapy, which exposes the entire body to cancer-fighting drugs, radiation therapy is usually a local treatment. It affects only the part of the body being treated. In the case of radioactive substances that are given in the vein or by mouth, the radiation does travel throughout the body. Generally, the radioactivity collects in the area of the tumor so that there is little effect elsewhere.

Do the Benefits Outweigh the Risks, Side Effects, and Costs?

Radiation therapy may be more helpful in some situations than in others. For example, some types of cancer are more sensitive to radiation than others, and some cancers are in areas that are more easily treated with radiation without causing major side effects.

If your doctor is recommending radiation therapy, it is because he or she feels that the benefits you may get from it are likely to outweigh the possible side effects. Still, this is something you must be comfortable with. Knowing as much as you can about the possible benefits and risks can help you decide whether radiation therapy is best for you. Questions to ask your doctor might include the following:

• What is the purpose of radiation treatment for my type of cancer? To destroy or shrink the tumor? To prevent or stop the spread of the cancer? To lessen the chance the cancer may come back? 
• If radiation therapy is to follow surgery, what are the chances it will destroy any remaining cancer cells? Could radiation alone be used instead of surgery? 
• What are the chances that radiation therapy will work? 
• What is the chance that the cancer will spread or come back if I do, or do not, have radiation therapy? 
• Are there other treatment options? 
• If I decide on radiation therapy, what can I do to be ready for treatment? 
• What will treatment involve? How often is it given? How long will it last? 
• How will the radiation affect the area around the cancer? 
• What side effects am I likely to have? 
• Will any of these side effects affect my ability to function normally, such as my ability to eat or drink, exercise, work, etc.? 
• Will side effects change how I look? 
• Will they be temporary or permanent? If temporary, how long will they last? 
• Will I be at higher risk for any other health problems in the future?

Is Radiation Treatment Expensive?

Treatment of cancer with radiation can be costly. It requires 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 plans, including Part B of Medicare, cover charges for radiation therapy. Talk with your doctor's office staff or the hospital business office about your health plan and how costs will be paid.

In some states, Medicaid (which makes health care services available to people with financial need) may help pay for treatments. Call your city or county social services office to find out if you are eligible for Medicaid and if radiation therapy is a covered expense. If you need financial aid, contact your hospital's social service office or the American Cancer Society at 1-800-ACS-2345 (1-800-227-2345) to learn about possible sources of help.

Who Gives Radiation Treatments?

During your radiation therapy, you will have a team of medical professionals caring for you. Your team may include the following:

• Radiation oncologist: A doctor specially trained to treat cancer patients with radiation. He or she recommends your radiation treatment plan. 
• Radiation physicist: The person who makes sure the radiation equipment is working properly and gives you the correct dose as prescribed by your radiation oncologist. 
• Dosimetrist: Supervised by the radiation physicist, this person helps the doctor plan the treatment. 
• Radiation therapist or radiation therapy technologist: This person operates the radiation equipment and positions you for treatment. 
• Radiation therapy nurse: A nurse with special training in cancer treatment who can give you information about radiation treatment and side effects.

You may also need the services of a dietitian, physical therapist, social worker, dentist or dental oncologist, or other health care professionals.

Informed Consent?

Before treatment, you will be asked to sign a consent form giving the doctor permission to treat you with radiation and do the tests that are needed to plan your treatment. Although the details of the consent form may vary, it usually says that your doctor has explained to you how radiation therapy may benefit you, the possible risks, and your other treatment options. By signing the form, you are saying that you have received this information and that you are willing to be treated with radiation. It also means that you understand there is no guarantee that the treatment will work.

Before signing the consent form, be sure that you understand the following:

• the potential benefits of the treatment 
• how the treatment will be given, including how long it may last 
• the possible side effects, including when they usually show up and how long they last 
• when to call your doctor 
• what other treatment options are available for you

How Is Radiation Therapy Given?

Radiation therapy can be given in 2 ways: as external radiation and as internal radiation. Usually one or the other is used, but some patients receive both types of therapy.

External radiation (or external beam radiation) uses a machine that directs high-energy rays from outside the body at the cancer and some normal surrounding tissue. Most people receive external radiation therapy over several weeks during outpatient visits to a hospital or treatment center.

Internal radiation therapy (brachytherapy) uses a radioactive source in the form of a wire or pellet that is usually sealed in a small container called an implant. The implant is placed inside the body in or near the tumor. The radiation from an implant travels only a short distance, so it has very little effect on normal body tissues.

Sometimes, after a tumor has been removed by surgery, radioactive implants are put into the area around the incision to kill any tumor cells that may remain. Implants may either be left in the patient as a permanent implant or they may be removed after a certain amount of time.

Radiopharmaceuticals are another type of internal radiation therapy. They are radioactive drugs used for certain types of cancer, such as thyroid cancer or cancer that has spread to the bone (bone metastases). This is a type of unsealed radioactive source that is given by mouth or by injection and travels throughout the body. Treatment with radiopharmaceuticals often requires a brief time in the hospital

The different types of radiation therapy are described in the sections that follow.

Revised: 10/02/2007