RADIATION-THERAPY FOR RETINOBLASTOMA - A RETROSPECTIVE REVIEW OF 120 PATIENTS

Purpose: To characterize the patient population and treatment outcomes in patients with Retinoblastoma (RE) referred for External Beam Orbit al Radiotherapy (EBORT) to King Faisal Specialist Hospital & Research Centre (KFSH&RC), Riyadh, Saudi Arabia from 1976 to 1993. Methods and Materials: A retrospective study of 120 patients with RE affecting a t otal of 192 eyes. Patients were divided into three groups. Group A are 60 patients (64 eyes) treated with EBORT to the intact eye to preserv e vision. Reese-Ellsworth (RE) Staging was: 1: 12%; 2: 10%; 3: 12%; 4: 23%; and 5: 43%. Twenty-eight patients (47%) also received Vincristin e, Adriamycin, and Cyclophosphamide chemotherapy (C/T). Mean follow-up , per patient, was 48.5 months. Standard treatment until 1992 was 45 G y in 12 fractions of 3.75 Gy, three times weekly over 18 days. Assumin g the alpha/beta ratio for early effects and tumor control at 10, Tk = 21 days, T-pot = 5 days, then the Biological Equivalent Dose (BED) wa s 62 Gy(10) for early effects, and 101 Gy(3) for late effects. Group B are 28 patients (28 eyes) treated for curative intent with EBORT to t he orbit for locally advanced disease, usually after enucleation (24 e yes). Nineteen patients (83%) also had C/T. Mean follow-up was 22.6 mo nths. Group C are 37 patients with advanced disease treated with radio therapy for palliation. Seventeen (46%) also received C/T. Mean follow -up was 11.7 months. Results: Group A-following EBORT useful vision wa s retained in RE Stage 1 to 5: 7 of 7, 6 of 6, 4 of 8, 10 of 15, and 7 of 28 eyes, respectively. There was no significant difference between patients who received adjuvant chemotherapy and those who did not. Co mplications included cataract (27%), retinopathy (25%), vitreous hemor rhage(19%), and orbital deformities(11%). In Group B the local control rate was 71%. In Group C, 10 (27%) of the 37 patients were alive at l ast contact, and 27 (73%) were either terminal or dead of disease. Non e of Group A or B patients had positive CSF cytology, bone scan, or bo ne marrow examination. In Group C 19% had positive CSF cytology, and b one marrow, and 14% had a positive bone scan. Conclusions: 1) EBORT pr eserved useful vision in a significant proportion of patients even in eyes with advanced RE Stage RE, but longer follow-up is likely to reve al an even higher complication rate,vith this regime. 2) High dose per fraction probably contributed to the increased complications. 3) Chem otherapy did not demonstrate any effect on retaining vision in this st udy. 4) For disease that is confined to within the eye clinically and radiologically, invasive procedures for CSF cytology, bone marrow exam ination, and bone scan do not seem warranted. 5) The optimum technique , fractionation, and dosage for RE is still not well defined. (C) 1997 Elsevier Science Inc.