Radiobiological Mechanisms and Radiation Risks in Radiotherapy of Benign Diseases

摘要

Radiotherapy is effective, low-risk and low-cost treatment of a large variety of non-malignant diseases. In many countries, radiotherapy is regarded as treatment of choice in diseases such as osteoarthritis, periarthritis humeroscapularis, Dupuytren's disease, and acute sweat gland abscess, or for the prevention of heterotopic ossification after hip replacement surgery. The pathogenesis of the various indications for radiotherapy are very different, and so are the doses given which, between the different indications, range from doses given in curative radiotherapy of cancer to 1% of those dose's. This is a clear indication that very different mechanisms are responsible for the different therapeutic effects. Clonogenic inactivation of stem cells, which is the mechanism responsible for the success of curative radiotherapy of cancer, does not play any role in the therapeutic response to radiotherapy of any benign disease discussed here. Until recently, radiobiologists neglected research into the effects of radiotherapy of benign diseases. This may have contributed to the neglect of this important field of medicine by clinical radiotherapists. However, during the last few years, some research has been performed, and part of it has been published. In this review of radiobiological mechanisms, some of this research will be described in the context of the diseases in which they may play a role. The starting point of all research in this field has to be the specific pathogenesis of the respective disease and the availability of suitable animal or cell culture models. The most dramatic effects any radiotherapist may encounter in his work is in the treatment of a developing abscess, for example in an axillary sweat gland or a maxillar abscess. A dose of 0.5 Gy is the standard treatment. A few hours later, there is a miraculous resolution of pain, of oedema, of erythema. The next day when the patient comes to get another irradiation, very often the abscess has gone, without antibiotics, no pus formed, no surgery needed. The effect is even more dramatic than with high-dose penicillin.