Cases of neuroblastoma missed by the mass screening programs

Twenty-two reported cases of neuroblastoma missed by the mass screening programs were reviewed (six cases in Sapporo City where a quantitative measurement for both vanillylmandelic acid (VMA) and homovanillic acid (HVA) is used and 16 cases in the districts of qualitative judgment only for VMA), and some potential factors for missing a patient were discussed. Most of the 22 patients were diagnosed over 12 mo and had advanced clinical stages at diagnosis (III or IV). Of the 17 cases whose outcome in prognosis was available, nine cases were dead and only three cases were alive without any trace of tumor. Fluctuation in the amounts of urinary VMA and HVA seemed to be one of the causes for missing a patient, especially with a small tumor. The comparison about tumor wt, VMA and HVA amounts, and clinical stage between the 22 true positive cases in Sapporo City and 46 ones in the districts of qualitative methods, and the difference in detection rate between the two groups suggested that the qualitative methods missed more patients with a small tumor. The patients who had abnormally high amounts of HVA with low amounts of VMA accounted for a fairly large part of the missed cases in Sapporo City as well as in the districts of qualitative methods. To the contrary, no patient of this type was found even among the 22 true positive cases in Sapporo City.