Radiotherapy is an old cancera disease where abnormal cells split without control and spread to other nearby body tissue and/or organs treatment, discovered in the 1900s, that is now used at high doses to kill cancer cellsthe basic structural and functional unit of all living things and shrink tumours. You might know it more commonly as XRays, however, the radiation used in XRay scans is at a much lower dosethe amount of medication taken.
Radiotherapy is used to treat cancer by slowing or stopping its growth, and it’s also used to ease cancer symptoms in the case of palliative treatment.
Radiotherapy works because the high-energy ‘packets’ of electromagnetic radiation penetrate deeply into cells of the body, disrupting the structure and function of DNA (which is like our body’s instruction manual). Once the DNA is damaged, the cell can no longer grow and divide, which is what cancer cells do at such a rapid rate. So at high doses, radiotherapy either ultimately kills or slows the growth of cancer cells. Once these damaged cells die, they are broken down and removed by the body.
It must be noted that the action of radiotherapy is delayed – it does not kill cancer cells immediately. It takes days or weeks of regular treatment before their cell DNA is damaged enough for them to die. Additionally, they continue to keep dying for weeks or months after the radiotherapy treatment has ended.
There are 2 main types of radiotherapy – external beam and internal. The decision about which is used for treatment depends on a number of factors, including the cancer type, tumoura tissue mass that forms from groups of unhealthy cells size and location, tumour proximity to healthy body tissues, any other concurrent cancer treatment, the patient’s general health, age and medical history.
- External Beam Radiotherapy: radiation is aimed directly at the cancer through a large machine. The machine doesn’t touch the patient but can move around and change directions to attain the perfect aim. It is described as a ‘local’ treatment, treating a specific body part but not affecting the whole body.
- Internal Radiotherapy: a source of radiation (solid or liquid) is given to run through the body, giving radiation from within. When it’s liquid, it enters the body by being swallowed, through an IV line or injection, and the radiation becomes systemic (travelling in the bloodthe red bodily fluid that transports oxygen and other nutrients around the body throughout the body to kill cancer cells). When it’s solid, it is known as brachytherapya type of internal radiation therapy where radioactive material is placed inside or near a tumor to deliver targeted radiation, and it’s delivered more locally in the form of seeds, ribbons or capsules that are placed near the tumour and give off radiation for a while.
Different radiotherapy types are used to treat different cancers. External Beam Radiotherapy is used to treat many different types, and in the case of palliative carea variety of practices and exercises used to provide pain relief and improve quality of life without curing the disease, it can be used to shrink tumours so that related symptoms are eased, such as pain, difficulty breathing, bowelportion of the digestive system that digests food (small bowel) and absorbs salts and water (large bowel); also called intestines or bladdera hollow, muscular sac in the pelvis that stores urine incontinenceloss of control over release of urine or faeces. Systemic Radiation can be radioactive iodine (or I-131), treating certain types of thyroid cancer, or radionuclide therapy, treating advancedat a late stage, far along prostatea walnut-shaped gland in the male reproductive system that is responsible for producing semen - a bodily fluid that acts as a vessel for sperm transport during ejaculation cancer or gastroenteropancreatic neuroendocrine tumour. Systemic Radiation drugs can also be used to treat cancer-related pain. Brachytherapy is most often used to treat cancer of the head and neck, breast, cervix, prostate and eye.
For many people with cancer, radiotherapy may be the only treatment needed. However, often it is used in conjunction with other cancer treatments (either before, during or after), such as surgerytreatment involving removal of cancerous tissue and/or tumours and a margin of healthy tissue around it to reduce recurrence, chemotherapya cancer treatment that uses drugs to kill or slow the growth of cancer cells, while minimising damage to healthy cells, and immunotherapya treatment that uses a person's immune system to fight cancer. And as a result of its actions, healthy body cells can be collateral damage, which can cause significant side effects, such as fatiguea state of extreme tiredness or exhaustion, can be physical or mental, hair loss, headaches, vomiting, diarrhoeafrequent discharge of watery or loose stools from the body, difficulty breathing, mouth and skin changes, bladder and bowel problems, and fertility issues.
There is a limit to the amount of radiation that a person and particular parts of a person’s body can receive over the course of a lifetime, which may influence doctors’ decisions regarding successive treatments.
Ultimately, the use of radiotherapy in cancer treatment is very dependent upon the type of cancer, the location and stage of the cancer, the treatment intent, and the person’s history. It will also be a very individual experience because it will affect people differently, so it’s important for each patient to take it slowly and be gentle with themselves as they work out how best to get through the treatment.
If you have any further questions about radiotherapy or other cancer treatments, or you need support during the process, please get in touch with us at Rare Cancers Australia on 1800 257 600 or email [email protected]
Authored by Dr Emily Isham