Radiotherapy continues to play an important role in the treatment of cancer. Depending on the kind of cancer, it may be combined with chemotherapy in place of surgery or be administered in addition to surgical treatment. In this way, radiotherapy enables any cancer cells left in the tissue after surgery to be removed. On the other hand, radiotherapy can also be useful before surgical treatment in order to reduce the size of the tumour initially and make it easier to remove during the operation.
The radiotherapy machines used even make it possible to treat tumours located deep inside the body. Unlike drug therapy, radiotherapy is a procedure that acts locally. This is why the radiologist first pinpoints the exact position of the tumour with the aid of modern imaging methods – such as computed tomography (CT) or magnetic resonance imaging (MRI). This enables the radiation to be directed with precision at the tumour tissue.
This therapy works on the principle of generating high-energy rays that are stronger than, for example, UV light. These rays damage the genetic material (DNA) in body cells and cancer cells alike. Healthy body cells are able to recover from the radiation because they are capable of repairing damage to the genetic material. This is not the case with cancer cells: the biological functioning of tumour cells is altered to such an extent that the natural repair mechanisms no longer work. This results in the desired death of the cancer cells.
The effect on healthy body cells causes treatment side effects. These include tiredness, skin irritation and mucous membrane irritation. Generally speaking, these side effects disappear once radiotherapy has finished. The radiation dose required for successful treatment is calculated individually for each patient. To reduce the treatment's stress on the body, the total dose is not administered all at once but is divided into several smaller doses (fractionated) over several treatment visits.