Prognostic Significance of Extent of Tumor Regression at Completion of Radiation Therapy

Abstract

If among tumors of a given volume and anatomical site there were subpopulations which differed in their local radiocontrollability or TCD502 (radiation dose that Yields a 50 per cent local control rate) and if these groups had distinguishing clinical characteristics, the radiotherapist could administer reduced radiation doses to the low TCD50 cases. This would lessen the likelihood of complication in that group of cases for a specified local control rate. For the higher TCD50 groups, either the treatment could be carried to maximum tolerable radiation doses by complex technics or the patient could be referred for surgery. In our center, decision as to the final radiation dose to be used in the treatment of individual squamous-cell carcinomas of the head and neck region has been based on the tacit assumption that each tumor at a specified site and a given volume could be classified as of a low, standard, or high local radiocontrollability group by observing the extent of regression of tumor volume at the c...