LAUSR

BACKGROUND With epidemiologic analyses of population-based trends in incidence and outcomes, we ascertained progress against non-Hodgkin's lymphoma (NHL) in children and young adolescents in the Netherlands since 1990. METHODS Tumour characteristics were extracted from the Netherlands Cancer Registry for patients aged <18 years at diagnosis, between 1990 and 2015. Mortality data for 1980-2016 were derived from Statistics Netherlands. NHL subtypes comprised lymphoblastic lymphoma (LBL), Burkitt lymphoma (BL), diffuse large B-cell lymphoma (DLBCL) and anaplastic large cell lymphoma (ALCL). Time trends in incidence and mortality rates and 5-year overall survival (OS) rates were evaluated by average annual percentage change (AAPC) analyses and parametric survival models, respectively. RESULTS Overall incidence of NHL remained stable at 11 per million person-years (AAPC -0.2%, p = 0.68), with a marked decrease among children of 5-9 years (AAPC -2.6%, p < 0.01), especially among those with BL. Treatment regimens comprised less radiotherapy over time, especially for LBL and BL. Since 2004, most 15-17-year-old patients with NHL have been treated at a paediatric oncology centre. Five-year OS improved from 71% in 1990-94 to 87% in 2010-15 (p < 0.01), the most gain has been achieved in patients with DLBCL and ALCL from 60% and 73%, respectively, to both 90%. Population-based mortality from NHL decreased significantly towards 1.4 per million person-years (AAPC -4.2%, p < 0.01). CONCLUSIONS This population-based epidemiological study exhibited significant progress against childhood and young adolescent NHL in the Netherlands since 1990, before the advent of a national paediatric oncologic centre in 2018: incidence decreased among children of 5-9 years, survival improved, and mortality steadily decreased over time.