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Radiation Oncology Overview

How is radiation therapy used?

Doctors can use radiation therapy in a number of ways to treat cancer.

  • Early stage cancer: radiation sometimes is the only treatment needed to shrink tumors or cause cancer cells to disappear
  • Before surgery: radiation is sometimes used before surgery to shrink a tumor so it can more easily be removed. 
  • After surgery: radiation may be recommended after surgery to keep any cancer cells that remain from growing.
  • With chemotherapy: radiation may be used in combination with chemotherapy to kill cancer cells.
How exactly does radiation therapy work?

All cells, healthy or not, grow and divide. Cancer cells grow and divide faster. Radiation changes the DNA inside a cancer cell so that it cannot grow. Radiation therapy targets only the tumor or location of the cancer and the area that surrounds it.

What types of radiation are used?

Doctors have several forms of radiation that can be used to kill cancer cells, depending upon where cancer cells are located. The radiation can come from outside of your body or be implanted.

  • External Beam Radiation Therapy – These radiation beams start outside of the body and are directed into the body to where the cancer cells are located. Higher doses of radiation typically can go deeper into the body’s tissues to reach the cancer. Doctors may use one or multiple radiation beams to treat cancer and can vary the amount of radiation from each beam. Beams also can be positioned to enter from almost any angle and be shaped to match the characteristics of a tumor.  External radiation can come in the form of x-rays, gamma rays, or proton beams, among others.
  • Internal Radiation Implants - Some types of cancer are treated with small “seeds” or implants of radioactive materials directly into or next to a tumor. This procedure is called brachytherapy. Implants can either remain in the body or be removed once depleted.
What types of cancer can be treated with radiation?

Early stage cancer and cancer known to spread to other specific areas of the body can benefit from radiation therapy. It can also be used to help kill remaining cancer cells that could still be hidden or undetected in your body. In some cancers, radiation therapy is recommended because it can help to relieve symptoms such as swallowing or breathing difficulty due to the location of a tumor.

How much radiation will I receive?

Your doctor will prescribe the exact type of radiation and dose needed. All patients receiving radiation therapy will be scheduled for pre-treatment planning sessions so that the location and size of your cancer or tumor can be mapped precisely.

Patients receiving radiation typically are scheduled for daily treatments (usually five days a week for a set period). The number of days depends upon the type and stage of cancer and where it is located as well as whether the radiation is combined with other treatments, such as surgery or chemotherapy. Typically, the length of time for radiation treatments ranges from two to eight weeks.

What types of radiation therapy are offered?

As a National Cancer Institute Comprehensive Cancer Center, the Siteman Cancer Center at Barnes-Jewish Hospital and Washington University School of Medicine offers a number of radiation therapy treatments for both children and adults. Renowned specialists at the Siteman Cancer Center oversee all radiation therapy treatments. Options available include

External Beam Radiation Therapy
Internal Radiation Therapy