Chiasmal
gliomas are rare
tumors occurring predominantly in children. Their treatment consists of surgery,
radiotherapy and
chemotherapy. Surgical removal can usually be only partial, and
radiotherapy frequently follows. There are supporters of
radiotherapy, as well as opponents. The author has been engaged in problems of optimal treatment of this entity for more than 10 years. He offers a review of knowledge provided by literature concerning
radiotherapy of this disease in children. In the past he was enthusiastic for
radiotherapy. Nevertheless after passing the Postgraduate course in paediatric neurosurgery in Bonn (1989), where J.F. Hirsch demonstrated very pessimistic progressive long-term harmful sequellae of irradiation of the developing child's brain, the author has re-evaluated his attitude to this
therapy. The short history and basic physical principles of
radiotherapy are reviewed. Some new trends of this
therapy are also mentioned (
hyperbaric oxygenation,
radiosensitizing agents,
hyperthermia etc.). Great attention is paid to the deleterious adverse effects of
radiotherapy and to the possible technical parameters enabling to avoid them (optional daily fractions, optimal total dose, limiting age in infants etc.). Harmful effects of
radiotherapy are reviewed in detail. The most frequent are chronic sequellae: brain
atrophy, radiation-induced brain
necrosis, progressive intellectual deterioration, growth retardation,
panhypopituitarism, galactorea,
learning disabilities, moya-moya
syndrome, radiation-induced secondary
brain tumors (especially
gliomas). Risks of
radiotherapy combined with
chemotherapy are also emphasized. Nevertheless
radiotherapy has remained an important therapeutical measure in the treatment of chiasmal
gliomas in children with progressive disease in cases when surgery and
chemotherapy have failed.