Retinoblastoma Incidence Patterns in the US Surveillance, Epidemiology, and End Results Program

Abstract

Retinoblastoma accounts for approximately 11% of cancers occurring in the first year of life, with 95% diagnosed before 5 years of age.¹ The origin of retinoblastoma involves a 2-hit mutational inactivation of the retinoblastoma gene RB1 (OMIM 614041).² In heritable cases (with a family history of retinoblastoma, known germline mutation, or multifocal disease), 1 hit is inherited as a germline mutation. Because only 1 additional hit is required in a somatic cell, heritable retinoblastoma occurs at a younger age relative to nonheritable cases, which require 2 hits in somatic cells.² Individuals with heritable retinoblastoma are also much more likely to develop multiple tumors, resulting in unilateral multifocal or bilateral disease, which has been used as a surrogate for heritable disease in the absence of RB1 mutation testing.³ With a well-established genetic origin, no significant changes in overall US retinoblastoma rates from the mid-1970s through 2004 have been reported.^1,4,5 Analyses using incidence data through the 1990s, however, revealed increasing rates among children younger than 1 year.^6,7 Higher incidence was also reported among females than males, blacks than whites, and white Hispanics than non-Hispanics.^4-6,8-12 Cancer registry data from the Surveillance, Epidemiology, and End Results (SEER) program are now available for 2005-2009. Our objective was to examine updated US retinoblastoma incidence patterns by sex, age at diagnosis, laterality, race/ethnicity, and year of diagnosis.