Radiation therapy for advanced cancer

Radiation therapy uses high-energy x-rays or particles to kill cancer cells or shrink tumors. For cancer that has not spread too far, radiation can sometimes cure the cancer, either by itself or used along with other treatments.

In advanced cancer, radiation therapy is often used to shrink tumors to reduce pain or other symptoms. This is called palliative radiation.

There are different types of radiation therapy and sometimes they are used together.

To learn more about radiation, please see Understanding Radiation Therapy: A Guide for Patients and Families.

For information on radiation treatment for a specific type of cancer, see our document about that type of cancer.

External beam radiation therapy

This is like having a regular x-ray except it lasts a little longer. A machine creates strong radiation beams that are directed at the tumor(s). Patients usually have treatments 5 days a week for several weeks. Sometimes, this can be shortened to just 1 or 2 days by giving more radiation during each session.

Special types of external beam radiation therapy are able to focus the radiation more precisely to lower some side effects. These include 3D-conformal radiation therapy (3DCRT) and intensity modulated radiation therapy (IMRT).

There is also a type of radiation that’s given in only a few sessions called stereotactic radiosurgery (steer-e-o-TACK-tick ray-dee-o-SUR-jer-ee). It’s called surgery, but no knife or scalpel is used. This treatment is used to treat tumors in the brain or spinal cord, and can allow the patient to avoid regular surgery. Using the same technique to treat cancer in other parts of the body is called stereotactic body radiation therapy.

Side effects of radiation often include extreme tiredness and skin changes ranging from redness to blistering and peeling in the skin the radiation beams passed through. Other side effects depend on the area being treated.

Radiation to the head and neck area can damage the glands that make saliva and cause a sore throat or mouth sores. Some people have trouble swallowing or lose their ability to taste food.

Radiation to the belly and pelvis can cause nausea, vomiting, diarrhea, and possible damage to the intestines. Radiation to the pelvis can irritate the bladder, leading to problems with burning with urination and a feeling like you need to go often.

Radiation to the chest area can irritate the esophagus (the tube connecting the throat to the stomach) leading to painful swallowing. It can also cause lung damage that may make some people short of breath.

Brain radiation can cause hair loss, as well problems with thinking or memory that can start many months to years after treatment.

Internal radiation therapy

This type of radiation is also called brachytherapy (brake-ee-THER-uh-pee). For this treatment the radioactive material is put right into or near the cancer. The radiation travels only a short distance, so there is less damage to nearby normal tissue. This is more often used for early-stage cancers, but is sometimes used to treat tumors blocking a lung or intestine.


Radiopharmaceuticals (ray-dee-oh-farm-uh-SUIT-ih-kulz) are a group of drugs that contain radioactive materials (such as radium-223, strontium-89 or samarium-153) that have been dissolved into liquids and can be given into a vein. They travel through the blood and are drawn to areas of bone that contain cancer. The radiation given off by the drug kills cancer cells and relieves bone pain, but it does not cure the cancer. If the cancer has spread to many bones, this may work better than using external beam radiation, which only treats a small area.

The major side effect of this treatment is lower blood cell counts (mainly white blood cells and platelets), which could increase your risk for infections or bleeding. This is more of a problem if your counts are already low before treatment.

Other radiopharmaceuticals aren’t only attracted to bones, but can be used to treat certain types of cancer, even when it has spread to other places. For example, radioactive iodine (I-131) can be used to treat most types of advanced thyroid cancer.

The American Cancer Society medical and editorial content team
Our team is made up of doctors and master’s-prepared nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

Last Medical Review: February 7, 2014 Last Revised: March 6, 2014

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