Radiation therapy. Trends in treatment

Newer techniques of radiation therapy seek to improve the therapeutic ratio in childhood brain tumors by adding potentially more effective treatment in ways that will limit radiation toxicities. In tumors marked primarily by local disease progression, the use of interstitial brain implantation "up front" or radiosurgery deserves systematic exploration. Whether local "boost therapy" with either of the latter techniques will add substantially to disease control and preserve neurologic function remains to be established both in malignant CNS tumors and in low grade gliomas. Radioactive colloids offer a potentially effective means of managing cystic tumors in children. Primary use in selected presentations (e.g., cystic astrocytomas or craniopharyngiomas in young children) is being tested in addition to trials addressing recurrent or progressive cystic lesions. The concurrent use of irradiation and radiosensitizing agents, especially cisplatin or the fluorocarbon emulsions is under investigation in pediatric tumors. Assessment of comparative efficacy and potentially heightened toxicities is important. There is considerable enthusiasm among all those caring for children with brain tumors to study modifications of radiation delivery that may result in improved treatment. Rapid accrual to an increasing number of prospective institutional or cooperative group trials should allow more informed decisions regarding the selection of newer radiation therapy modalities in the future.