RECURRENCE OF UNILATERAL RETINOBLASTOMA FOLLOWING RADIATION-THERAPY

A retrospective analysis of 65 unilateral retinoblastoma patients trea ted initially with external beam radiation, revealed that 25 eyes (38. 5%) developed local recurrence of retinoblastoma. The mean age at diag nosis was I.8 years for patients who developed recurrences vs. 0.9 yea rs for those who did not. Ninety-six percent of the recurrences occurr ed less than two years from the age at diagnosis; the amount of time f rom the end of external beam radiation treatment until a tumor recurre d was independent of the age at diagnosis. The initial largest basal d iameter was 10.7 DD for tumors which later recurred and 5.9 DD for tum ors that were cured. Sixty-nine percent of eyes in groups III-V had tu mor recurrence, and 10% of eyes in groups I-II had recurrence. All but one eye (24 eyes) that developed recurrence were enucleated. Family h istory of retinoblastoma, location of the tumor, gender, and lateralit y did not significantly correlate with the mean age of initial diagnos is for tumors that recurred or the mean time of onset for recurrence.