Cancer in children: radiotherapeutic approaches.

Radiotherapy is an important treatment modality for 40-50% of children with cancer. There is concern about late effects, particularly the neuropsychological effects of CNS irradiation, and orthopaedic effects. It is important to administer the highest standard of radiotherapy, incorporating departmental quality assurance. Meticulous planning is essential to achieve local tumour control with the minimum of irradiation to normal tissues in order to minimise late effects. Current developments include better definition of tumour extent with MR scanning, and the use of 3D planning and conformal techniques to precisely match the radiotherapy target volume to the tumour. For some CNS tumours the role of stereotactically directed radiotherapy is being explored. Interactions with chemotherapy are important to improve the therapeutic ratio, however increased normal tissue toxicity can be problematic. Radiotherapy for children should be undertaken only in departments linked to specialised paediatric oncology centres.