INCIDENCE AND SURVIVAL OF RETINOBLASTOMA IN THE NETHERLANDS - A REGISTER-BASED STUDY 1862-1995

Aim-The aim of this study was to determine the (time trends in) incide nce and survival of hereditary (familial and sporadic) and non-heredit ary retinoblastoma for male and female patients born in the Netherland s between 1862 and 1995.Method-The national retinoblastoma register wa s updated and now consists of 955 patients. The missing dates of death were obtained from the municipal registers and the Central Bureau of Genealogy in The Hague. Mortality was compared with the Dutch vital st atistics. Results-From 1862 to 1995 no significant differences in inci dence for retinoblastoma were found in the hereditary subgroups. Furth er, no significant differences between males and females were found, b oth overall and in the hereditary subgroups. The average incidence of retinoblastoma increased until 1944, probably due to incompleteness of the register, and stabilised after 1945 (1 per 17 000 live births). F rom 1900 to 1995 the standardised mortality ratio increased for heredi tary retinoblastoma patients from 2.9 to 9.0 and decreased for non-her editary retinoblastoma patients from 1.9 to 1.0. Conclusion-Although s urvival for retinoblastoma was significantly better after 1945 than be fore, in comparison with the Dutch population the mortality between 19 00 and 1990 increased for the hereditary and decreased for the non-her editary retinoblastoma patients.