The author has analyzed and summarized newer opinion to the point of the therapeutic ratio and possibilities of its modification in combined radiotherapy and chemotherapy in combination with the less radical surgical treatment. He has stressed the need of preservation of function, cosmeses, and the quality of life after treatment. He has analyzed the mechanisms and causes of failure of radiotherapy and chemotherapy. The endeavour of the therapy response improvement must respect mainly normal tissue tolerance. The recognizing of the influence of radiotherapy and chemotherapy to rapidly, slowly (conditionally), and non-proliferating (fixed) tissues is extremely important. It is then possible to recognize the risk of acute or late (chronic) damage of normal tissues. The basis of radiation changes is due to parenchymal cellular hypoplasia of stem cells and to alterations in the fine vasculature and fibroconnective tissues. The late effects of chemotherapy are postulated to be predominately a result of parenchymal cellular depletion of both non.cycling and cycling cells also, but with sparing of the microcirculation and bibroconnective tissue stroma. The author has given the survey of at present used fractionation schemes of radiotherapy and has stressed the advantage of multifractionation, especially from the point of view of late responding normal tissues sparing. At the end of this overview he has pointed to the great need for the search of tests (markers) for the early detection of acute damage and for the prediction of eventual late, occasionally life-threating toxicity.
Nex concepts of radiation-injury mechnisms and delayed chemotherapy toxicity
