Radiotherapy is a common treatment for many cancers and works by killing cancer cells using high-energy X-rays, electron beams or radiaoactive isotopes aimed at the tumour or cancer.
Radiotherapy may be used on its own, or in combination with other cancer treatments, including chemotherapy and surgery.
What types of radiotherapy are available?
Successful radiotherapy depends on delivering the correct amount of radiation to the cancer in the best and most effective way. There are several types of radiotherapy:
External beam radiotherapy
External beam radiation is the most common form of radiotherapy. Treatment is preceded by detailed planning or simulation. During simulation, a team of specialists, including a radiotherapy oncologist, will use measurements from scans and calculations to determine where precisely to aim the radiation. They will tattoo small dots on your body showing where to target the beam, so that the same location is radiated at every treatment. This process may take several hours
During the treatment, you will be positioned on a table so that a beam from a machine outside the body can be aimed at the tumour. The radiation treatment itself lasts only a few minutes, but it may be given five times a week for several weeks, and sometimes a couple of times a day for several weeks.
Internal systemic radiotherapy involves injecting radioactive isotopes either into a vein or into an organ. One of the most common types of systemic radiotherapy is radioactive iodine (I-131), which is given for some types of thyroid cancer. Another type of systemic radiotherapy is the use of Strontium 89 (Metastron). This isotope is used to treat cancer that has spread to the bone.
Interstitial radiotherapy (also known as brachytherapy) is where radioactive sources are implanted into tissue at or near the tumour site. These sources may be temporary (removed after the correct dose is reached) or permanent.
Intracavitary radiotherapy is used most commonly in gynaecological cancers, such as cancer of the uterus. In this procedure, radioactive sources are placed in applicators that are positioned in the area affected. They are left in place for several hours and then removed. The patient must stay in bed at the hospital while the radiation is in place. In some patients with early rectal cancer, intracavitary radiotherapy is a successful treatment.
What are the side-effects of radiotherapy?
The side-effects of radiotherapy are, for the most part, specific to the area of the body being radiated. Among the more general side-effects may be skin irritation and fatigue. Other side-effects may include nausea and vomiting (for radiotherapy given in the stomach area), hair loss (for radiotherapy given to the head), sore throat and difficulty swallowing (for radiotherapy given to the neck or chest), and diarrhoea (for radiotherapy given to the lower back or abdomen).
There are medications and techniques that can help to control side-effects. Make sure you discuss any side-effects with your doctor so they can be managed properly.