EXTERNAL-BEAM RADIOTHERAPY FOR RETINOBLASTOMA .2. LENS SPARING TECHNIQUE

A retrospective analysis is presented of the results of external beam radiotherapy for retinoblastoma utilising an accurate lens sparing tec hnique. Local tumour control has been assessed in a consecutive series of 67 eyes in 53 children all of whom received external beam radiothe rapy as the primary treatment of retinoblastoma. Follow up ranged from 12 to 82 months (median 35 months) with 76% of the children followed for more than 2 years. Tumour control rates have been analysed with re spect to the Reese-Ellsworth classification. The role of adjuvant and salvage focal therapy is emphasised. Following lens sparing radiothera py with prior adjuvant treatment of anterior tumours, where appropriat e, the overall ocular cure rate was 72%. With salvage therapy of persi stent, recurrent, or new tumours, 93% of eyes could be preserved in th is series which includes mainly eyes classified in Reese-Ellsworth gro ups I-III. These results compare favourably with those of whole eye ex ternal beam radiotherapy for comparable tumours, and with those of len s and anterior segment sparing using other techniques. They were achie ved without the ocular morbidity associated with whole eye external be am radiotherapy.