Background Canceris rare before age 20years.We aimed to use the European database of childhood and adolescent cancer cases,within the Autom ated Childhood Cancer In-form ation System project,to estim ate patterns and trends of incidence and survivalwithin Europe. M ethods Com para- ble,high-quality data from 63European population-based cancer registries consisted of113000tum ours in children and 18243in adolescents diagnosed in 1970-99.Inci- dence rates and survivalwere com pared by region (eastvs west),period,and m alignant disease.Findings In the 1990s,age-standardised incidence rates were 140per m illion for children (0-14years)and 157per m illion for ages 15-19years.O ver the three decades,overall inci- dence increased by 1.0% per year (p <0.0001)in chil- dren (increases for m ost tum our types),and by 1.5% (p <0.0001)in adolescents (15-19years;notable in- creases were recorded for carcinom as, lym phom as,and germ -celltum ours).O verall5-year survivalfor children in the 1990s was 64% in the eastand 75% in the west, with differences between regions for virtually all tum our groups;5-year survival was m uch the sam e in adoles- cents.Survivalhas improved dram atically since the 1970s in children and adolescents,m ore so in the westthan in the east.Interpretation Our results are clear evidence of an increase ofcancerincidence in childhood and adolescence during the past decades,and of an acceleration of this trend.Geographicaland tem poralpatterns suggestareas for further study into causes of these neoplasm s,as well as providing an indicatorofprogress ofpublic-health policy in Europe. Background Canceris rare before age 20years. We aimed to use the European database of childhood and adolescent cancer cases, within the Autom ated Childhood Cancer In-formtion System project, to estim ate patterns and trends of incidence and survivalwithin Europe. M ethods Com para - ble, high-quality data from 63European population-based cancer registries consisted of113000tum ours in children and 18243in adolescents diagnosed in 1970-99.Incitence and survivalwere commented by region (eastvs west), period, and m alignant disease. Findings In the 1990s, age-standardized incidence rates were 140per m illion for children (0-14years) and 157per m illion for ages 15-19years. Of the three decades, overall inci- dence increased by 1.0% per year (p < 0.0001) in chil- dren (increases for most tum our types), and by 1.5% (p <0.0001) in adolescents (15-19 years; notable in- creases were recorded for carcinom as, lym phom as, and germ-cellllum ours) .O verall5-year survival for children in the 1990s was 64% in the east and 75% in the west, with differences between regions for virtually all tum our groups; 5-year survival was m uch the sam e in adoles- cents. Survivalhas improved dram atically since the 1970s in children and adolescents, m ore so in the westthan in the east.Interpretation Our results are clear evidence of an increase of cancer incidence in childhood and adolescence during the past decades, and of an acceleration of this trend. Geographicaland tem poralpatterns suggestareas for further study into causes of these neoplasm s, as well as providing an indicator of progress of public-health policy in Europe.