Retinoblastoma: an epidemiological study (survey and review).

An epidemiological study of retinoblastoma patients from Buffalo, New York, and Rio de Janeiro, Brazil, was conducted at Roswell Park Memorial Institute in 1974. Several important differences were uncovered as a result of this study. Patients in Buffalo with bilateral retinoblastoma were diagnosed most often within the first year of life and those with unilateral retinoblastoma after about 24 months of age. This difference in diagnostic age between the two forms of retinoblastoma is not demonstrated by the patients from Rio de Janeiro. Most of the Rio de Janeiro patients are 24 months or older before either type of retinoblastoma is diagnosed. By this time the disease has usually extended beyond the eyeball, and orbital exenteration is deemed necessary. Because the patients in Rio de Janeiro are diagnosed at an older age, these patients have a shorter length of survival and higher mortality as compared to the patients in Buffalo. Additional differences that were derived from this study will require further research for verification.