More About Second Cancers After Retinoblastoma

Abstract

In 1973, Strong and Knudson (1) predicted that second cancers would occur at an increased rate in survivors of retinoblastoma, that only those with the genetic form of the tumor would be at risk, and that radiation therapy (RT) would increase the risk. Beginning with a report from the Late Effects Study Group in which retinoblastoma emerged as the most common primary cancer—it occurred in 52 of 292 children with more than one malignant disease (2)—many other cohort studies have confirmed this increased risk (3–8). The genetic form of the disease includes all children with bilateral disease (although the majority have a negative family history and are due to new germline mutations), patients with unilateral disease and a positive family history, and patients in whom genetic analysis has confirmed a mutation in RB1. Because genetic analysis of RB1 was performed in some members of the cohort described by Marees et al. (10) in this issue of the Journal, it would be interesting to know how many unilateral cases were added to the genetic list based on mutation analysis.