Use of irradiation for therapy of retinoblastoma in children more than 1 year old: the St. Jude Children's Research Hospital experience and review of literature.

Fifteen children (> 1 year old at diagnosis) were treated for retinoblastoma (RB) with primary irradiation at St. Jude Children's Research Hospital between January 1963 and January 1992. Staging of the 19 treated eyes was as follows: Reese-Ellsworth (R-E) Groups I and II, n = 7; Group III, n = 3; Group IV, n = 1; Group V, n = 7; information on one globe is incomplete. Total dosage ranged from 25 to 45 Gy (median = 40 Gy) in fractions of 170-225 cGy delivered 5 x/week (n = 13) or 225-265 cGy delivered 4 x/week (n = 4 eyes) or x 5/week (n = 2 eyes). Treatment techniques included anterior field (n = 11) or lens-sparing technique (n = 8). One patient has died of progressive central nervous system (CNS) disease at 13 months; one patient succumbed to second malignant neoplasm within the irradiated field at 194 months; the remaining 13 patients remain alive from 27 to 301 months (median = 178 months). Local control with irradiation alone has been maintained in 12 eyes. Four eyes with local recurrence were salvaged using cryotherapy or reirradiation. Enucleation was required for three eyes for progressive disease at 4, 7, and 7 months postirradiation. Cataract formation was documented in nine eyes treated with anterior fields and in one patient treated with lens-sparing technique. At last follow-up, 7 patients had visual acuity of 20/100 or better. Radiation dose of 40 Gy appears to be adequate for local control of early stage RB (R-E Groups I-III and VB whose tumors are R-E Groups I-III) in patients > 1 year old. The results of this limited series which has lengthy follow-up is compared with the results of previously published data in an effort to define the benefits and disadvantages of the different treatment techniques which have been reported in the treatment of RB in children > 1 year old.