Overview
As part of your cancer treatment plan, your doctor may recommend radiation treatment. Radiation therapy targets cancerous tumors, killing or damaging them so they can’t grow, multiply or spread. Your radiation oncology team at Oklahoma Cancer Center offers the latest technologies to prescribe and deliver this type of treatment.
How Radiation Therapy Works Against Cancer
Radiation therapy uses high-energy radiation to target and destroy cancer cells. It’s used in the early stages of cancer treatment or after it has started to spread. The goal of radiation therapy is to deliver precise doses of radiation to the tumor while minimizing damage to healthy surrounding tissues.
Radiation therapy does not kill cancer cells right away. It takes days or weeks of treatment before DNA is damaged enough for cancer cells to die. Then, cancer cells keep dying for weeks or months after radiation therapy ends.
Types of Radiation Therapy
There are two main types of radiation therapy, external beam and internal.
The type of radiation therapy that you may have depends on many factors, including:
- Type of cancer
- Size of the tumor
- Tumor’s location in the body
- How close the tumor is to normal tissues that are sensitive to radiation
- General health and medical history
- Whether you will have other types of cancer treatment
- Other factors, such as your age and other medical conditions
External Beam Radiation
External beam radiation therapy comes from a machine that aims radiation at your cancer. The machine is large and may be noisy. It does not touch you, but can move around you, sending radiation to a part of your body from many directions.
External beam radiation therapy is a local treatment, which means it treats a specific part of your body. For example, if you have cancer in your lung, you will have radiation only to your chest, not to your whole body.
Proton therapy is an advanced form of radiation treatment that suits many types of cancers and tumor types. If a physician recommends radiation therapy as part of a patient’s cancer treatment, proton therapy is likely an option. Unlike common radiation treatments that use X-rays or photons such as IMRT and Cyberknife, protons have a unique physical property that allows radiation oncologists to precisely target a patient’s cancer and stop the protons inside the tumor, avoiding healthy tissue and organs.
Tomotherapy® is a type of IMRT that uses a machine that is a combination of a CT scanner and an external-beam radiation machine. This system combines 3D imaging and Intensity Modulated Radiation Therapy (IMRT) delivery to precisely target cancer.
Internal Radiation Therapy
Internal radiation therapy is a treatment in which a source of radiation is put inside your body. The radiation source can be solid or liquid.
Internal radiation therapy with a solid source is called brachytherapy. In this type of treatment, seeds, ribbons, or capsules that contain a radiation source are placed in your body, in or near the tumor. Like external beam radiation therapy, brachytherapy is a local treatment and treats only a specific part of your body.
With brachytherapy, the radiation source in your body will give off radiation for a while.
Internal radiation therapy with a liquid source is called systemic therapy. Systemic means that the treatment travels in the blood to tissues throughout your body, seeking out and killing cancer cells. You receive systemic radiation therapy by swallowing, through a vein via an IV line, or through an injection.
With systemic radiation, your body fluids, such as urine, sweat, and saliva, will give off radiation for a while.
Why People with Cancer Receive Radiation Therapy
Radiation therapy is used to treat cancer and ease cancer symptoms.
When used to treat cancer, radiation therapy can cure cancer, prevent it from returning, or stop or slow its growth.
When treatments are used to ease symptoms, they are known as palliative treatments. External beam radiation may shrink tumors to treat pain and other problems caused by the tumor, such as trouble breathing or loss of bowel and bladder control. Pain from cancer that has spread to the bone can be treated with systemic radiation therapy drugs called radiopharmaceuticals.
Types of Cancer that are Treated with Radiation Therapy
External beam radiation therapy is used to treat many types of cancer.
Brachytherapy is most often used to treat cancers of the head and neck, breast, cervix, prostate, and eye.
A systemic radiation therapy called radioactive iodine, or I-131, is most often used to treat certain types of thyroid cancer.
Another type of systemic radiation therapy, called targeted radionuclide therapy, is used to treat some patients who have advanced prostate cancer or gastroenteropancreatic neuroendocrine tumor (GEP-NET). This type of treatment may also be referred to as molecular radiotherapy.
How Radiation is Used With Other Cancer Treatments
For some people, radiation may be the only treatment you need. But, most often, you will have radiation therapy with other cancer treatments, such as surgery, chemotherapy, and immunotherapy. Radiation therapy may be given before, during, or after these other treatments to improve the chances that treatment will work. The timing of when radiation therapy is given depends on the type of cancer being treated and whether the goal of radiation therapy is to treat the cancer or ease symptoms.
When radiation is combined with surgery, it can be given:
- Before surgery, to shrink the size of the cancer so it can be removed by surgery and be less likely to return.
- During surgery, so that it goes straight to the cancer without passing through the skin. Radiation therapy used this way is called intraoperative radiation. With this technique, doctors can more easily protect nearby normal tissues from radiation.
- After surgery to kill any cancer cells that remain.
