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Radiation-Therapy

Radiation therapy

This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science at CTCA.

This page was updated on April 22, 2022.

How does cancer radiation therapy work

How does cancer radiation therapy work?

What is radiation therapy?

Radiation therapy (also called radiotherapy) uses targeted energy, including X-rays and radioactive substances, to destroy cancer cells, shrink tumors and/or alleviate certain cancer-related symptoms. Doctors use high-energy X-rays and other forms of radiation therapy to damage the DNA in cancer cells, killing them or depriving them of their ability to grow or divide.

It may be used:

  • As a primary treatment to destroy cancer cells
  • In combination with other treatments to stop the growth of cancer cells
  • Before another treatment to shrink a tumor
  • After another treatment to stop the growth of any remaining cancer cells
  • To relieve symptoms of advanced cancer

Radiation therapy does not kill cancer cells immediately. Over several days and weeks, and during the course of treatment, the DNA in cancer cells may become damaged enough that they die or are no longer able to reproduce.

Radiation therapy is one of the most common types of cancer treatments. At least half of all patients receive radiation therapy to treat their cancer. Radiation therapy may be used to treat both benign and malignant tumors. 

At Cancer Treatment Centers of America® (CTCA), our radiation oncologists are experienced in using advanced technologies to deliver targeted radiation therapy while also proactively managing side effects. From treatment planning to follow-up, our comprehensive cancer centers provide personalized patient care and state-of-the-art radiation oncology services to help you fight cancer and manage its symptoms.

Types of radiation

Some radiation therapy delivery methods include:

  • External beam radiation therapy: Radiation is directed from a machine outside the body onto cancerous cells within the body. Examples include 3D conformal radiation therapy, intensity-modulated radiation therapy (IMRT), image-guided radiation therapy (IGRT), TomoTherapy®, proton therapy, stereotactic radiosurgery.
  • Internal radiation therapy (Brachytherapy): Radioactive material is placed (via a catheter or other carrier) directly into or near a tumor. Examples include high-dose rate brachytherapy.
  • Systemic radiation therapy: A radioactive substance (that is swallowed or injected) travels through the blood to locate and destroy cancerous cells. Examples include radioactive iodine therapy.

Managing radiation side effects

Typical radiation therapy can be damaging to the body and cause unpleasant side effects, such as skin changes, fatigue, nausea and other issues, depending on the part of your body being treated. During your radiation treatment, radiation therapists and clinicians from a variety of supportive care services will work with you to reduce side effects and improve your quality of life.

Some parts of the body may be more sensitive to radiation therapy than others. And radiation therapy has dosage limits. If a part of the body has been treated with radiation therapy before, radiation therapy  may no longer be a treatment option in that area. Talk to your doctor if you’ve had radiation therapy before to discuss dosage limits to the area being treated.  

Six tips for staying hydrated

As important as it is to stay hydrated when you’re well, studies show it’s essential during cancer treatment. However, maintaining hydration may be a challenge for patients who are unable to consume enough fluid or who lose too much due to the symptoms of the disease or side effects of treatment.

Staying hydrated

Experienced care team

Our radiation oncology team specializes in delivering high radiation doses to tumors with less damage to normal tissues and organs. Our radiation oncologists will work closely with you and the rest of your cancer care team to deliver radiation therapy based on your individual needs.

Individualized treatment approach

Radiation therapy is an important part of treatment for many of our cancer patients. Since each cancer type requires a different approach, your treatment options will depend on your unique needs and treatment goals.

Our radiation oncologists use advanced imaging techniques before and during radiation treatment so we can closely track the tumor. We use highly targeted radiation technologies to deliver high radiation doses to tumors, with techniques designed to have less impact on healthy tissues and organs.

Depending on your individual needs, you may receive radiation therapy alone or in combination with other treatment modalities like surgery, chemotherapy, hormone therapy and/or immunotherapy. Throughout your treatment, your radiation oncologist will monitor the progress of your radiation therapy regimen and modify your treatment plan as needed.

How to prepare for radiation therapy

Each patient’s experience with radiation therapy differs depending on the type of technology used, the type of cancer being treated and other factors. Before your course of treatment begins, your doctor will explain the type of radiation equipment to be used and discuss your treatment schedule and length of treatment. You’ll also undergo an examination.

Your doctor may place marks on your skin or fiducial markers near the tumor to allow him or her to quickly find the target treatment area. You may also be fitted with devices designed to immobilize parts of the body during treatment. These steps are intended to help doctors better focus radiation more directly on the tumor and avoid exposing surrounding healthy tissue.

In most cases, radiation therapy is delivered in an outpatient procedure over a period of days or weeks. Some patients may undergo treatment every day for a period of time. Others may be scheduled over several weeks.

Radiation therapy is typically a relatively quick and painless treatment, and many patients are able to resume their normal activities before and after treatment. Over time, patients may need to adjust while experiencing common side effects, such as fatigue or irritation to the skin.

Cancer treatments are often stressful, upset your normal routines and take a physical toll. It’s important to take steps to help stay physically strong during the course of treatment, including by:

  • Getting plenty of rest
  • Staying hydrated
  • Eating well
  • Staying vigilant about side effects or physical changes

At CTCA®, our supportive care providers will work with you to help address and, when possible, prevent side effects so you’re better able to maintain your strength, stamina and quality of life, during and after your cancer care.

Radiation therapy can be delivered externally or internally. The type of radiation therapy a patient receives may depend on a variety of factors, such as the type of cancer and the size and location of the tumor(s) to be treated. 

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