Radiotherapy in tumors of childhood

Abstract

Phillips and Dargeon provided an excellent overview of the progress of radiotherapy in the treatment of childhood cancer since Roentgen's discovery in 1895. At the time, even short-term remissions for childhood cancer were rare, and radiotherapy was the most “formidable” therapeutic option available, although the actual value of ionizing radiotherapy was uncertain. Combination modality therapy (chemotherapy and radiotherapy) was considered desirable but unproven, so the authors advocated increased use of radiotherapy in the treatment of childhood cancer. They admitted, however, that the knowledge needed to treat childhood cancer scientifically was “pitifully inadequate.” During the last 50 years, through cooperative multicenter research studies, our knowledge has improved greatly. Through better surgical and diagnostic techniques and combined modality therapy, short- and long-term remissions of childhood malignancy are now common. The utility of radiotherapy was clearly demonstrated in 1971 when prophylactic whole-brain radiation was shown to greatly improve the survival of children with acute lymphoblastic leukemia.1 In 1954, the knowledge of long-term side effects of radiation was inadequate. Certain complications such as dry skin, cataracts, and pulmonary fibrosis had been recognized, but survival of children with cancer was so poor that the long-term sequelae were not fully appreciated. Now that most children are surviving, long-term complications such as neurocognitive disabilities, hormonal dysfunction, growth abnormalities, and secondary sarcomas, have become apparent. In large part due to these complications, radiotherapy has decreased in importance. For example, radiotherapy in 1954 was standard therapy for Wilms' tumor. However, the results of the National Wilms' Tumor Study Group research conducted since 1969 have allowed for the elimination of radiotherapy from all except the most advanced stage patients, and survival has continued to improve.2 As predicted in 1954, improvements in radiotherapy methods and changes in its indications have been dramatic. Our hope is that through continued cooperative studies, treatments will continue to improve survival of childhood cancer while further decreasing both acute and long-term side effects.