Radiation therapy; Radiotherapy
Radiation therapy (also called radiation therapy) is a cancer treatment that uses high doses of radiation to destroy cancer cells and shrink tumors. In low doses, radiation is used in x-rays to see inside the body, such as x-rays of teeth or broken bones.
❯ How Cancer Radiation Therapy Works
In high doses, radiation therapy destroys cancer cells or slows their growth by damaging their DNA. Cancer cells whose DNA is irreparably damaged stop dividing or die. When damaged cells die, they break down and are discarded by the body. Radiation therapy does not immediately destroy cancer cells. It takes days or weeks of treatment before the DNA is damaged enough for the cancer cells to die. The cancer cells then continue to die weeks or months after radiation therapy ends.
❯ Types of radiation therapy
There are two main types of radiation therapy, external beam and internal radiation therapy. The type of radiation therapy you may need depends on many factors, such as:
- The type of cancer
- The size of the tumor
- The location of the tumor in the body
- How close the tumor is to normal radiation-sensitive tissues
- Your overall 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 therapy
External beam radiation therapy comes from a machine that focuses radiation on your cancer. The machine is large and can be noisy. It doesn't touch you, but it can move around you and send 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 your entire body.
Internal radiation therapy
Internal radiation therapy is a treatment in which the radiation source is put into 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 the body at or near the tumor. Like external beam radiation therapy, brachytherapy is a local treatment and treats only a specific part of the body.
With brachytherapy, the radiation source in the body will emit radiation for some time.
Internal radiation therapy with a liquid source is called systemic therapy. Systemic therapy means that treatment is carried in the blood to tissues throughout the body where it locates and destroys cancer cells. Systemic radiation therapy is given by mouth or through a vein, intravenous line, or injection.
With systemic radiation, body fluids (urine, sweat, and saliva) will emit radiation for some time.
❯ Why people with cancer receive radiation therapy
Radiation therapy is used to treat cancer and relieve symptoms of cancer. When used to treat cancer, radiation therapy can cure the cancer, stop it from coming back, or stop or slow its growth. When treatments are used to relieve symptoms, they are known as palliative treatments. External beam radiation can shrink tumors to treat pain and other problems caused by the tumor, such as shortness of breath or poor bowel and bladder control. Pain caused by cancer that has spread to the bones can be treated with systemic radiation therapy medications 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 often used to treat head and neck, breast, cervix, prostate, and eye cancers. Systemic radiation therapy uses radioactive iodine, or I-131, is most often used to treat certain types of thyroid cancer. Another type of systemic radiation therapy, called radionuclide targeted therapy, is used to treat some patients with advanced prostate cancer or with a gastroenteropancreatic neuroendocrine tumor and a gastroenteropancreatic neuroendocrine tumor (NET-GEP). This type of treatment may also be referred to as molecular radiation therapy.
❯ How radiation is used with other cancer treatments
For some people, radiation may be the only treatment they need. But, in most cases, radiation therapy is possible 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 the treatment will work. The length of time radiation therapy is given depends on the type of cancer being treated and whether the purpose of radiation therapy is to treat the cancer or relieve symptoms.
When radiation is combined with surgery, it can be given:
- Before surgery so that the radiation reduces the size of the cancer and can be removed by surgery and is less likely to return.
- During surgery, so that 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 more easily protect normal tissues near radiation.
- After surgery, to destroy cancer cells that may have remained.
❯ Dose Limits in Life
There is a limit to the amount of radiation that an area of your body can safely receive in the course of your life. Depending on the amount of radiation an area has already been treated with, you may not be able to receive radiation therapy in that area a second time. But, if one area of the body has already received the safe dose of radiation for life, another area could still be treated, if the distance between the two areas is large enough.
❯ Radiation therapy can cause side effects
Radiation not only destroys or slows the growth of cancer cells, it can also affect healthy cells around you. Damage to healthy cells can cause side effects. (Source from the National Cancer Institute, NIH)
What is Radiosurgery?
The Intracranial Stereotactic Radiosurgery or SRS for its acronym in English (Stereotactic Radiosurgery), is a treatment technique that allows concentrating high doses of radiation in a small and precise area of the brain, respecting to the maximum neighboring structures, all achieved through the principles of stereotaxy.
Its creator was the Swedish neurosurgeon, Dr. Lars Leksell of the Karolinska Institute in Stockholm, Sweden, along with biophysicist Professor Börje Larsson. Although the word includes the term "surgery," it is a treatment and not a surgical procedure. It is minimally invasive, painless, does not require admission or recovery in an intensive care unit, nor does it require general anesthesia, is 100% ambulatory and the patient can return to their daily tasks almost immediately.
All patients must be evaluated by a multidisciplinary medical team. Depending on the location, size of the lesion, nearby organs and type of tumor, the dose to be administered and the number of sessions required will be decided.
What is Brachytherapy?
The word "brachys" comes from the Greek and means near or at a short distance. Brachytherapy is a treatment where a radiation source is introduced as close as possible to the tumor or area where it was located.
It can be used in the breast, prostate, esophagus, bronchi, soft parts and frequently in the endometrium and cervix, among others. The dose and duration of exposure is anticipated and the introduced materials can be left on site or removed. In the particular case of the cervix, it should be administered as a complement to radiotherapy.
The American Society for Brachytherapy (ABS) supports its use as an integral component of the definitive treatment of locally advanced cervical cancer. The standard non-surgical curative treatment for this type of cancer includes a combination of Chemotherapy, External Radiation Therapy and Brachytherapy.
