Oncological surgical procedures, thanks to the implementation of the latest global medical technology advances, are becoming safer for the patient and possible to carry out, with the intention of a cure, even in the most advanced proliferative processes. Radiation treatment devices (radiotherapy) are being developed with an eye to ever-improving working precision, enabling targeted treatment, focused on the tumour lesion, with minimal strain on critical organs in the vicinity. The addition to oncology treatment of drugs from other groups, also new and successively modified and improved on the basis of previous experience with patients, makes it possible to more fully prevent the side-effects of oncology treatment, which is a burden.
Radiotherapy
Radiotherapy of cancer uses the energy of ionising radiation. In addition to radical oncological treatment (e.g. for oesophageal cancer, tumours of the central nervous system, certain types of gonadal tumours), it has applications in relieving pain associated with disseminated cancer, e.g. secondary lesions - metastases in the skeletal system (common in advanced breast cancer, prostate cancer).
Radiotherapy specialists qualify patients for radiation therapy according to the recommendations for the type of cancer and its stage. They use devices that emit X-rays (X-rays), gamma rays, electrons, alpha particles and neutron radiation. Cancer cells are damaged by irradiation by two mechanisms. Firstly, by directly damaging the DNA of the cancer cells secondly, indirectly, through oxygen free radicals generated by the radiolysis of water molecules, which damage structures that are important for the life and proper functioning of the cell.
With regard to the method of irradiating the tumour tissue, radiotherapy is divided into teletherapy and brachytherapy.
Teletherapy, i.e. irradiation from external sources, uses ionising radiation emitted by a device at a suitable distance from the patient's body. The range of tissues affected by the radiation includes the cancerous tumour and a margin of healthy tissues surrounding it. Before treatment commences, it must be planned in an appropriately meticulous manner - the patient undergoes multiple imaging examinations (CT scans, MRI scans), which are performed in the appropriate projections and positions, and numerous measurements are taken - planning - an exact, limited irradiation field. The aim is to concentrate the treatment beam as precisely as possible in the centre of the tumour with the best possible protection of the surrounding, healthy tissues in order to avoid the distant effects of radiation on the so-called critical organs (the most radiation-sensitive organs). To ensure due precision, the areas to be irradiated in each subsequent session are marked on the patient's skin.
Brachytherapy (also known as contact radiotherapy) is used for the precise local treatment of malignant tumours. The radiation source (e.g. caesium Cs137, cobalt Co60, radium Ra226, yttrium Y90 and others) is placed directly into the organ affected by the tumour - on the surface (e.g. to treat skin tumours - e.g. squamous cell carcinoma of the skin), in natural body cavities (intracameral brachytherapy - e.g. uterine cavity in the case of endometrial cancer, oral cavity for tumours in this location). In some centres, brachytherapy is carried out in combination with surgery-intraoperatively, e.g. after removal of breast cancer.
Based on the dose rate and the stage of the cancer in the patient undergoing irradiation, we distinguish between radical radiotherapy, palliative radiotherapy and symptomatic radiotherapy.
Radical radi otherapy is carried out with the intention of cure- irradiating the tumour and its surroundings to achieve complete remission. In more advanced lesions, where the operability of the tumour is doubtful or where distant secondary lesions are found and the patient will undergo chemotherapy as a first-line treatment, palliative treatment is sometimes implemented after careful analysis of the patient's history in an attempt to alleviate pain and other discomforts associated with the tumour (e.g. palliative irradiation of the oesophagus in a patient with dysphagia and inoperable tumour in this location). Symptomatic radiotherapy is the treatment of cancer pain caused by limited metastases to the skeleton (pelvic bones, ribs, spinal vertebrae), e.g. breast cancer or prostate cancer.
The effectiveness of radiotherapy depends not only on the stage of the lesion and the primary location of the cancer, but also on the radiosensitivity of the tumour tissue - a concept understood as the percentage of tumour cells that die after a test dose of radiation. In the case of highly radiosensitive tissue, at least 70 per cent of the tumour cell colonies will die after irradiation with the test dose, unlike in the case of tissue with poor sensitivity, where only up to 20 per cent of the cells undergo necrosis. Increasing the tumour mass directly proportionally increases the risk of necrotic foci or areas of ischaemia in the centre of the tumour, which reduces radiosensitivity many times over.
photo: panthermedia
For tissues with low radiosensitivity, the use of radiotherapy is associated with a less desirable therapeutic effect with a greater risk of adverse effects. Highly radiosensitive tumours include malignant granuloma, non-Hodgkin's lymphomas, some subtypes of leukaemia, immature sarcomas and medulloblastomas, and Ewing's sarcoma in children. Tumours characterised by low radiosensitivity, on the other hand, include embryonal carcinomas, smooth muscle sarcomas, chondrosarcomas, carcinomas and sarcomas with a mucosal, synovial and fatty component, malignant melanoma.
