How does radiation therapy (RT) treat cancer?

Radiation (also called radiotherapy, x-ray therapy, or irradiation) can be used alone or in combination with other treatments for cancer, such as chemotherapy, surgery, or biological therapy. It is a conventional medical therapy that can help:
  • Kill cancer cells
  • Shrink tumors
  • Stop cancer cells from growing and dividing

Healthy cells are affected during radiation, but most appear to recover after treatments. Doctors will control the intensity of the radiation and the area affected to keep the side effects to a minimum.

How it's used: Radiation is administered at a hospital or treatment center in internal or external forms. Internal radiation requires a radioactive substance sealed in a container to be implanted into a tumor or body cavity. Sometimes an unsealed source is used and is taken orally or by injection. External radiation requires a machine that will direct high-energy rays at the tumor and surrounding area.

Side effects: Radiation side effects vary from person to person. The most common are: fatigue, skin changes, and a decrease in appetite.

Susan McCloskey, MD
Radiation Oncology
Radiation therapy damages the DNA of cancer cells. DNA is the genetic material of cells and it controls how cells grow and divide. When the DNA of cancer cells is damaged, the cells are unable to effectively repair the damage and they die. Fortunately, normal cells are able to efficiently repair DNA damage. As a result, even though some normal tissue is injured during radiation treatment, the normal tissue usually recovers while the cancer cells are killed.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.