What is radiation therapy? When is it used?

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

Radiation therapy is one of the most common treatments for cancer. It is often part of the main treatment for certain 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 getting radiation treatments. Radiation can be given alone or combined with other treatments, such as surgery or chemotherapy. And sometimes patients get more than one type of radiation therapy.

How does radiation therapy work?

All cells grow and divide to form new cells. But cancer cells grow and divide faster than many of the normal cells around them.

Radiation therapy uses special equipment to deliver high doses of radiation to the cancer cells. This kills or damages them so they cannot grow, divide, or spread. Radiation works by breaking a piece of the DNA molecule inside the cancer cell, which keeps the cell from growing and dividing. Some nearby normal cells may be affected by radiation, but most fully recover from the effects of the treatment and go back to working the way they are supposed to.

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. The goal of radiation treatment is to damage as many cancer cells as possible, with little harm to nearby healthy tissue.

In some cases radioactive substances may be given in a vein or by mouth, then the radiation does travel throughout the body. But for the most part, the radioactive substance collects in the area of the tumor so that there is little effect on the rest of the body.

Do the benefits outweigh the risks and side effects?

Radiation therapy may be more helpful in some cases 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 recommends radiation treatment, it is because he or she feels that the benefits you may get from it will 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 be done after surgery, what are the chances it will destroy any cancer cells that were left behind? Could radiation 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 how I do things, such as eat or drink, exercise, work, etc.?

• Will side effects change how I look?

• How long will the side effects last?

• Will I be at higher risk for any other health problems in the future?

How much does radiation treatment cost?

Treating cancer with radiation can cost a lot. 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 Medicare Part B, cover the charges for radiation therapy. Talk with your doctor's office staff or the hospital business office about your health plan and how your bills for treatment 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 qualify for Medicaid and if radiation therapy is a covered expense. If you need financial help, contact your hospital's social service office or the American Cancer Society at 1-800-ACS-2345 (1-800-227-2345) to learn where you might get more 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 people:

• Radiation oncologist: A doctor specially trained to treat cancer patients with radiation. He or she is in charge of your radiation treatment plan.

• Radiation physicist: The person who makes sure the radiation equipment is working as it should and gives you the dose prescribed by your radiation oncologist.

• Dosimetrist: Supervised by the radiation physicist, this person helps the radiation oncologist 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. This form gives the doctor permission to treat you with radiation and do the tests that are needed to plan your treatment. The details of the consent form may vary, but 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 gotten this information, that you understand it, 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 these things:

• the potential benefits of the treatment
• how the treatment will be given, including how long it will 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 3 ways: as external radiation, as internal radiation, or as systemic radiation. In some cases more than one type of therapy is used.

External radiation (or external beam radiation) uses a machine that directs high-energy rays from outside the body into the tumor and some normal nearby tissue. Most people get external radiation therapy over many weeks. It is done during outpatient visits to a hospital or treatment center.

Internal radiation therapy (also called brachytherapy) uses a radioactive source in the form of a wire, seed, or pellet that is called an implant. The implant is put inside the body in or near the tumor. The radiation from the implant travels only a short distance, so it has very little effect on normal body tissues. In some cases, patients may need to stay in the hospital while getting internal radiation.

Sometimes, after a tumor has been removed by surgery, radioactive implants are put into the area where the tumor was to kill any tumor cells that may still be there.

Implants may either be left in the patient as a permanent implant or they may be removed after a certain amount of time.

Systemic radiation is another type of internal radiation therapy. Radiopharmaceuticals are used for this treatment. Radiopharmaceuticals are radioactive drugs used to treat certain types of cancer, such as thyroid cancer or cancer that has spread to the bone (bone metastases). These drugs are unsealed radioactive sources that can be given by mouth or by injection, which then travel throughout the body. Treatment with radiopharmaceuticals often requires a brief time in the hospital.

The different types of radiation therapy are described in more detail in the next sections.

Last Medical Review: 12/23/2008
Last Revised: 12/23/2008