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Historic milestones in radiobiology and radiation therapy.

1979; National Institutes of Health; Volume: 6; Issue: 4 Linguagem: Inglês

Henry S. Kaplan,

Management of metastatic bone disease

R ADIATION THERAPY came into existence as a new modality of treatment for cancer almost immediately after the discovery of x-rays by Riintgen, of radioactivity by BecquereL2 and of radium by the Curies,3 shortly before the turn of the century. By 1899, a report had already appeared of the apparent cure of the first cancer, a basal cell epithelioma, treated by this new technique. Thus, the entire history of radiation therapy as a treatment modality now encompasses only about 80 yr.4 The initial responses of skin cancers and other superficial neoplasms treated by irradiation were so dramatic that they generated the unrealistic expectation that a miraculous cure for all cancers had finally been discovered. This unrealistic view was soon succeeded by a wave of disillusionment and pessimism when tumor recurrences and injuries to normal tissues began to appear. Yet, it would have been remarkable indeed if such discouraging experiences had not occurred during that early era, for the first 25 yr of this new discipline were indeed the “dark ages” of its evolution. Since there were no training programs in radiation therapy, virtually all of its early practitioners were dermatologists or surgeons. These early radiation therapists had no understanding of the physical nature of the new and mysterious agents with which they worked, nor did they have any comprehension of their biologic effects. There were no reliable methods with which to measure dose, and no generally agreed unit of dose existed. Equipment was primitive, temperamental, and too limited in energy to permit any but the most superficial neoplasms to be treated. The early radiation therapists initially adopted treatment techniques involving massive exposures aimed at the eradication of tumors in a single treatment, comparable to the extirpation of tumors by surgery.5 It is thus not surprising that the primary morbidity, and even the acute mortality, of such massivedose treatment was often comparable to that of major surgery of that day. Patients who survived the immediate postirradiation period often experienced impressive partial or complete regression of their tumors, but these initial responses were all too often followed by major complications, as