INTRODUCTIONIt is unknown whether screening for neuroblastoma has the benefit of reducing the incidence of advanced diseaseor mortality due to neuroblastoma.Japanese nationwide massscreening for 6 month old infants was launched in 1985 and was performed using quantitative high-performance liquid chromatography (HPLC) between years 1990 to 2003.

MATERIALS AND METHODSWe compared the incidence rates (IR) and the mortality rates (MR) per 100,000 births of neuroblastomas diagnosed before 6 years of age between 2 cohorts: children born during the years 1980 to1984 (Pre-screen cohort, n = 7,620,203) and 1990 to1998 (Screen cohort, n = 10,878,918). We then proposed the optimal timing and procedures for future screening.

RESULTSCumulative IR in the Screen cohortwas significantly higher than the Pre-screen cohort (29.80 vs. 11.96, P <0.0001). On the other hand, IR of neuroblastoma diagnosed after 24 months old in the Screen cohort was significantly lower than in the Pre-screen cohort (P <0.0001). The cumulative MR of the Pre-screen cohort was 5.35, whereas that of the Screen cohort was 2.82 (P <0.0001).

CONCLUSIONSHPLC mass-screening for neuroblastoma at 6 months of age found a marked increase in incidence in younger children (less than 12 month old) and a significant decrease in mortality rates overall. To reduce overdiagnosis of regressing cases and to identify preclinical stages of unfavourable cases, we propose using HPLC-screening at 18 months of age.