Patients with germinal retinoblastoma (those with bilateral disease or
positive family history) have a mutation which puts them at risk for
developing new tumors. It is unclear whether the frequency of new tumo
r development is effected by the type of treatment employed. It may be
hypothesized that external beam radiation 'sterilizes' the whole reti
na, and thus decreases the risk of new and recurrent tumors. We review
ed our experience with 66 eyes in 47 patients over the past ten years.
We did not find a significant difference in the incidence of new and
recurrent retinoblastoma among eyes treated with external beam radiati
on versus focal modalities.