Overview (What it is, why it is used and how it works)
Radiotherapy or radiation therapy treats cancer by using high energy beams to destroy cancer cells. The beams can be in the form of x-rays, gamma rays, electron beams or protons. High doses of radiation kill cancer by causing small breaks in the cells’ DNA. This prevents the cells from multiplying and results in the cells dying off. Once these cells have been destroyed, they are broken down and removed by the body. Cancer cells do not die straight away and it may take multiple treatment sessions, administered over a length of time to ensure the DNA is sufficiently damaged for the cell to die. The cells continue to die off for weeks, or even months after radiation treatment ends.
When Radiotherapy is used as a treatment
More than half of all cancer patients can expect to receive some form of radiation therapy. In some cases, radiation therapy alone is enough to cure cancer but in others, it is used in combination with other forms of cancer-fighting treatments.
Radiation therapy can be used to shrink tumours before, during or after surgery or to reduce pain, pressure and other cancer symptoms when a cure is not possible.
Types of Radiation Therapy
- External beam therapy is the most frequently used form of radiation therapy. In this treatment energy beams are aimed at the location of the cancer in the body.
- Internal radiation therapy or brachytherapy is when small pieces of radioactive material are placed inside the body close to the site of cancer. These implants can be in the form of a tube, wire, capsule, pellets or seeds and may be temporarily or permanently inserted. The radiation source can be a solid form, like a pellet, or a liquid.
While some patients will receive only one treatment of radiation therapy, most will receive treatment for five days a week over a period of a few weeks.
How it is administered
An external radiation therapy session is quick and lasts around 15 minutes. The patient will simply lie down and the machine that sends the energy beams, will be pointed at the site of cancer in the body. The treatment is painless but side effects may develop over time. Only the targeted site and some surrounding tissue will be affected.
There are two ways internal radiation therapy can be administered. If a patient is receiving an implant, it will be inserted into the relevant section of the body while the person is under anaesthesia.
With systematic internal radiation therapy, the patient is given a liquid which travels through the blood into tissue throughout the body. This can be given orally, intravenously or by injection.
Side effects of Radiation Therapy
During radiotherapy healthy cells that also divide rapidly may be affected during therapy which results in various side effects. Once the treatment is completed, any damage to healthy cells will repair and side effects will disappear.
Side effects may include:
- Flaky, itchy, dry or red skin
- Hair loss
- Dry mouth, difficulty chewing and swallowing, and tooth decay
- Chest issues which may include coughing, shortness of breath and painful swallowing
- Abdominal problem such as diarrhoea
- Nausea, vomiting or loss of appetite
- Sexual dysfunction