Mass screening of neuroblastoma in Sapporo City, Japan.

In Sapporo City a mass screening program for neuroblastoma aiming at 6-month-old infants has been performed since April 1981. By March 1990, 136,001 infants were screened; 26 true-positive cases of neuroblastoma and six false-negative cases were detected. The sensitivity of the mass screening method was about 80% throughout the 9 years. During the 9-year period, a total of nine children with neuroblastoma who were not screened were also identified. Clinical stage, age at diagnosis, and survival rate for the 32 patients who were screened (26 true positives and six false negatives) were much more favorable than those for the nine patients who were not screened. A remarkable decrease in the incidence of cases of neuroblastoma with advanced clinical stages over 1 year of age, especially among children 1-4 years of age, was noted after the start of the mass screening. The mortality from this tumor in children up to 4 years of age significantly decreased after the start of the urinary screening program. Rescreening at 14 months of age was begun in April, 1991 in Sapporo City. Performing two screening examinations decreases the probability of overlooking a patient. Thus, it is expected that tumors missed on the first screening would be detected by the second screening.