The evolution of the basic concepts underlying the practice of radiotherapy from 1949 to 1977.

In his overview of the history and theoretical developments of radiotherapy, the author stresses the following concepts: (a) sensitivity is not linked to histology but to the volume of cancer; (b) the dose must not necessarily be homogeneous in the target volume but related to varying volumes of cancer; (c) the fact that irradiation may not be the sole treatment in some tumors does not mean that it does not have a place in their management; (d) as a general rule, large tumors should not be treated with irradiation only, if gross cancer can be resected simply; (e) since there is a dose-response curve for control rates and for complications, an optimum dose level must be maintained; and (f) the patient's quality of life is a major concern.