Retinoblastoma in Finland, 1964-2014: incidence and survival

Abstract

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

Methods: 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.

Results: 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.

Conclusion: 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.

Keywords: child health (paediatrics); epidemiology; neoplasia; retina.