Radiation Therapy


Radiation therapy is a powerful treatment tool that can target and destroy cancer cells in a specific area of the body. More than half of cancer patients undergo radiation treatments for one of the following purposes:

  • To destroy small, early-stage tumors.
  • To shrink a tumor before surgery.
  • To kill lingering cancer cells after surgery or other treatments. This helps prevent cancer from coming back.

People with incurable cancer may also have radiation therapy. “Palliative radiation” shrinks tumors that cause pain, breathing trouble or other problems

Radiation therapy may be the only treatment you need, or it may be combined with other treatments such as chemotherapy or cancer surgery.

Types of Radiation Therapy

Cancer-killing radiation is a form of energy that exists as waves or charged particles. These include X-rays, gamma rays, electron beams and protons. 

Radiation therapy is given in one of three ways and the type of radiation therapy you’ll need depends on several factors. These include the size and location of your tumor, what organs are near the tumor and whether you also need other cancer treatments.

External Beam Radiation

External beam radiation uses a machine to send radiation through your body and into the tumor. External beam radiation can treat a broad range of cancers, including brain and spine tumors, and cancers of the lung, breast, prostate, bladder, liver and bones. Mercy offers most forms of external radiation. These include:

Internal Radiation Therapy

Internal radiation, also known as brachytherapy, uses a radioactive implant. It’s placed inside your body, in or near the tumor. Brachytherapy is often used to treat head and neck cancer, breast cancer, cervical cancer, endometrial cancer, prostate cancer and eye cancer.

Systemic Radiation

Systemic radiation uses radioactive drugs to treat certain tumors, including thyroid cancer and metastatic prostate cancer.

Radiation Therapy Risks

Like any medical treatment, radiation therapy poses potential risks. These include:

  • Radiation therapy may cause temporary side effects. These commonly include fatigue, loss of appetite, loss of hair in the treatment area, or skin changes (such as redness, itching or peeling).
  • If you have brachytherapy or systemic radiation, your body might temporarily give off tiny amounts of radiation while the implant or medicine is active. Your doctor will tell you if you should limit contact with pregnant women or young children.
  • Radiation can harm a fetus. Women must take steps to avoid becoming pregnant during treatment.
  • People exposed to radiation have a higher chance of getting another cancer later in life. However, for most patients, the risk of cancer returning without radiation is much higher than the risk of radiation causing a new cancer in the future.
  • Radiation can harm healthy cells next to your tumor. Many will heal and continue to function once your treatments are over.

If your doctor recommends you have radiation therapy, it’s because he or she believes the benefits outweigh the risks. Your care team will carefully plan your treatments to ensure they are safe and effective. If you have questions or concerns about radiation therapy, please talk to one of your Mercy caregivers.

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