Current Topics in Clinical Radiobiology of Tumors (Medical Radiology / Radiation Oncology) - Tapa dura

The impact of basic science radiobiological research is now being recognized of significant importance in clinical radiation oncology. Observations made in the laboratory using animals as'well as tissue culture have led to a better biologic understanding of techniques for altered fractionation, techniques for measuring tumor cell proliferation, the possi­ bilities and limitations of methods for evaluation of nonrandomized clinical studies in deriving time dose relationships for human tumors as well as a better understanding of repair kinetics in mammalian cells, fractionation sensitivity and the major impact oftechnologies to improve local/regional control with the subsequent impact on survival. These findings have led to changes in treatment schedules and have led to further close cooperation among the radiation oncologists and radiation biologists. Well support research efforts in radiation biology have a major and significant impact on the clinical care of the cancer patient. Studies that originated in the laboratory are now finding their way into clinical practice resulting in better local and regional control and improved number of patients surviving without disease.

This provides an update of topics that at present constitute the main controversies in the field of clinical radiobiology. A critical appraisal is given of the clinical results obtained so far by the application of hyperfractionation and accelerated fractionation. In addition, the possibilities and limitations of the methods for evaluation of nonrandomized clinical studies to derive time-dose relationships for human tumours, the use of the BUDR technique for determination of tumour proliferation characteristics, the validity of the linear-quadratic model at low doses per fraction, the predictive value of SF2 for the outcome of radiotherapy, and methods for the identification of hypoxic cells are critically reviewed.