How does radiation therapy work in cancer treatment?

This is an automatically translated article.

Posted by Specialist Doctor II Bui Le Phuoc Thu Thao - Radiation Therapist - Oncology Center - Vinmec Central Park International General Hospital. The doctor has nearly 15 years of experience in direct treatment of cancer patients, especially radiation oncology and care for terminal cancer patients, palliative care and pain relief.
Radiation therapy is a cancer treatment that uses high-energy X-rays to kill cancer cells and shrink tumors. Specifically, how does radiation therapy work in treating cancer? The following article will answer that question for you.

1. How does radiation therapy kill cancer cells?

The term "radiotherapy" is commonly used to refer to the use of a radiotherapy machine that delivers radiation from outside the body to a target volume inside the body, which is the volume to be treated, usually a malignant tumor. count.
At high doses, radiation therapy destroys the DNA of cancer cells, causing them to die or grow slowly. Cancer cells with damaged DNA cannot repair themselves and therefore stop dividing or die. The body breaks down and removes the dead cancer cells.
Radiation therapy does not kill cancer cells immediately, so it takes days or weeks of treatment before the DNA is damaged enough for the cancer cells to die. Then, the cancer cells continue to die for several weeks or months after the radiation therapy ends.

2. Types of radiation therapy

Currently, there are two main types of radiation therapy, internal radiation therapy and external radiation therapy. And it depends on many factors for the doctor to decide which type of radiation therapy is best for the patient, including:
The type of cancer The size of the tumor Where the tumor is in the body How close tumor and avoid radiation-sensitive healthy tissue Medical history and current health Other cancers associated Age. External Beam Radiation Therapy
The radiation source is the beam generator (X-ray generator, accelerator, Cobalt-60 radiation therapy machine...) through the collimator irradiated from outside. body to the part to be treated. The machine does not touch the patient's body, but can move around the person and shoot radiation to the part to be treated from many different directions.
External radiation therapy is a local treatment, which means it treats a specific part of the body. For example, if you have lung cancer, you will only have radiation therapy to the chest area, not the whole body.
Internal Radiation Therapy
Internal radiation therapy uses radioactive sources in the form of seeds or capsules containing radioactive material that are placed in or near the tumor. Like external radiation therapy, internal radiation therapy is a local treatment and treats only a specific part of the body. Internal radiation therapy, also known as brachytherapy, allows doctors to deliver a higher dose of radiation to a specific area of ​​the body than external radiation, with less effect on nearby healthy organs. Brachytherapy may cause fewer side effects than external radiation therapy.
Another commonly used internal radiotherapy technique is radiopharmaceutical therapy. This therapy uses drugs (radioactive isotopes) in liquid form (called systemic radiation). Systemic means that the radioactive material used for treatment travels through the bloodstream to all tissues in the body, looking for and killing cancer cells. The drug will be given by mouth or by intravenous infusion. With systemic radiation, the patient's body fluids such as urine, sweat, and saliva also release radioactive material after treatment.

3. Why do cancer patients need radiation therapy?

Radiation therapy is used to treat cancer and to help relieve symptoms of the disease. When used, radiation therapy can cure cancer, prevent it from coming back, or slow the growth of cancer cells, helping people to live longer.
When treatments are used to relieve symptoms, it is called palliative care. External radiation can shrink tumors to treat pain and other problems caused by the tumor, such as compression of the tumor causing difficulty breathing or loss of bowel and bladder control.

4. What type of cancer is indicated for radiation therapy?

External radiation therapy is used to treat many types of cancer.
Brachytherapy is commonly used to treat head and neck cancers, breast, cervical, prostate.
In systemic radiation therapy is used called radioactive iodine or I-131, which is commonly used to treat certain types of thyroid cancer. Another type of systemic radiation therapy is targeted radionuclide therapy, which is used to treat advanced prostate cancer or gastrointestinal neuroendocrine tumor.

5. Combination therapy with radiation therapy

In some cases, only radiation therapy is needed, but in most cases radiation therapy is combined with other cancer treatments, such as surgery, chemotherapy, and immunotherapy. Translate. Radiation therapy may be given before surgery to reduce tumor irritation or given during or after other treatments to work together to increase the effectiveness of treatment. The timing of radiation therapy depends on the type of cancer and whether the goal of radiation therapy is to treat the cancer or relieve symptoms.
Radiation therapy is combined with surgery when:
Before surgery, to shrink the size of the tumor and then the tumor can be completely removed by surgery and there is little chance of recurrence. During surgery, the radiation goes directly to the cancer without going through the skin. Radiation therapy used in this way is called intraoperative radiation. With this technique, doctors can easily protect the healthy tissue around the tumor from radiation. After surgery to destroy any remaining cancer cells. The most commonly used radiotherapy machines are called linear accelerators (or collectively, the Linac machines). The Truebeam radiotherapy machine used at Vinmec International General Hospital is the newest and most modern Linac machine of Varian, USA.

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References: Livescience.com, Cancer.gov
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What is radiation therapy? The role of radiation therapy How does radiation therapy work? Side effects of radiation therapy