Retinoblastoma in Finland, 1964-2014: incidence and survival

To determine the incidence of retinoblastoma (Rb) and subsequent survival in the Finnish population during five decades.

This retrospective observational cohort study comprised all patients with Rb born in Finland during 1964-2014 and diagnosed in 2018 (birth cohort analysis) or diagnosed in 1964-2014 (standard annual analysis), identified from the Finnish Cancer Registry and the national referral centre. We report age-adjusted incidences and survival according to cause of death.

Of children born in 1964-2014, 205 developed Rb, whereas 204 Rbs were diagnosed during these years; 196 belonged to both cohorts. Altogether 80 (38%) of the 213 children had heritable Rb and 19 (9%) had familial disease. The sex ratio was 1.34, suggesting male preponderance. Birth cohort analysis showed a median incidence of 6.2 per 100 000 live births (1:16 130) and less variability as compared with standard annual analysis (12.1, 6.5 and 4.4 per million children 0-4, 0-9 and 0-14 years of age, respectively). The incidence of heritable Rb increased with time, reflecting the increase in familial tumours. Five-year mortality rates from Rb were 6.2% and 7.6% for non-heritable and heritable diseases, respectively, and 35-year mortality rates from second malignancies were 0% and 14.3%, respectively. Family history predicted improved survival, whereas the period of diagnosis did not.

The incidence of familial Rb has increased, along with improvement in survival in Finland in 1964-2014, whereas the overall incidence of Rb was stable. Long-term risk of dying of second malignancies after heritable Rb was in line with other countries.