Retinoblastoma

Retinoblastoma is a rare, highly malignant tumour of the retina which predominantly affects young children. The growth originates from single or multiple foci in the retina of one or both eyes. The tumour may occur either sporadically or may be inherited. Retinoblastoma is extra-ordinary in its medical, genetic and therapeutic significance. The irradiation method which has been used for the conservative treatment of retinoblastoma at Utrecht since 1971 is described. Treatment is carried out on a 6 MeV or 8 MeV linear accelerator using a lateral D-shaped field of 26x32 mm2. This D-shaped field is especially contoured to irradiate the entire retina with sparing of the radiosensitive lens as much as possible. Between 1971 and 1980, 30 children with retinoblastoma have received irradiation to at least one eye using the accurate irradiation technique. The results of treatment of these patients are presented. In the treatment it is not always possible to entirely exclude the lens from the treatment field. As a consequence, cataract may be induced. (Auth.)