Purpose: The comparable health-care organizations and common Cancer Registry for childhood malignancies in the five Nordic countries offered an opportunity to conduct an epidemiological study on a reasonable number of childhood non-Hodgkin's lymphoma (NHL) cases collected in a population-based manner.
Material and methods: All childhood cases (0-14.9 years at diagnosis) reported during the 5-year period of 1985-1989 to the Nordic Society of Pediatric Hematology and Oncology (NOPHO) Cancer Registry for childhood malignancies were reviewed and analyzed according to age, Murphy's stage, gender, site, and survival.
Results: The annual incidence of NHL is 0.7 per 100,000 children in the five Nordic countries, constituting 5% of all childhood malignancies. Age distribution was even; the male/female ratio was 3:1. Age and stage were shown by Cox regression analysis to be independent prognostic factors. Older age and lower stage affected outcome favorably. The stage and site distribution was similar to previous reports. Survival data were in accordance with those expected with modern treatment protocols.
Conclusions: The incidence and relative frequency of NHL in childhood in the five Nordic countries is in agreement with previously reported data, but the even distribution of cases throughout childhood is a new finding. Older age at onset and stage of disease affect outcome favorably, whereas male gender contrary to acute lymphoblastic leukemia was not found to affect outcome.