Educational and regional differences in population-based incidence and survival of primary central nervous system...

BACKGROUND: This is the first nationwide population-based study to assess educational and regional differences in the incidence and survival of primary central nervous system lymphoma (PCNSL) in Finland. METHODS: Data were extracted from the Finnish Cancer Registry based on the histological diagnosis and tumor location for cases of large B-cell lymphoma (LBCL) between 2007 and 2022. Data were divided into five healthcare regions of the Finnish healthcare system, which included 623 PCNSL patients (48% female), 27% of whom had higher education, 34% had secondary education, and 39% had primary or unknown education. The incidence rates of PCNSL and LBCL were calculated and the proportion of PCNSL incidence to LBCL incidence was estimated. The age-standardized relative survival rates were calculated within subgroups defined by educational level and healthcare region. RESULTS: The annual proportion of PCNSL incidence to LBCL incidence remained stable at 6.5% between periods 2007–2014 and 2015–2022 in Finland (p = 0.324). The age-adjusted incidence rate standardized by the World Health Organization World Standard Population (WHO WSP 2000–2025) was 0.54/100,000 person-years. The incidence rates did not differ between healthcare regions (p = 0.097) or between groups defined by educational level (p = 0.725). From 2007 to 2022, the 2-year and 5-year age-adjusted relative survival rates were 38% and 30%, respectively. In between healthcare regions, the 2-year age-adjusted relative survival rate varied between 25% and 56%, and the 5-year age-adjusted relative survival rate between 16% and 45% (p < 0.001). No statistically significant difference in survival rates was observed according to the educational level (p = 0.282). CONCLUSIONS: The incidence of PCNSL in Finland remains one of the highest observed in population-based studies. However, the proportion of PCNSL incidence to LBCL incidence remained stable between periods 2007–2014 and 2015–2022. The incidence rates did not differ between educational levels or healthcare regions. A minor trend towards improved survival was observed among those with a higher educational level. Remarkable differences were observed in survival after diagnosis of PCNSL according to patients’ healthcare regions.