Is the mass screening for neuroblastoma ineffective?

Though a recent study (Schilling et al. 2002) concluded that the mass screening for neuroblastoma targeting children age 12 months was ineffective, we pointed out several serious problems and reestimated its effectiveness using their data. They employed the subjects in the "control area" as controls, not the "non-participants" whose biases are fewer because their area is the same as that of the participants. The incidence of neuroblastoma among the subjects in the "control area" was about 25% smaller than that of the "non-participants". This leads to underestimation of the effectiveness of the mass screening. They combined false negatives with true positives to calculate the incidence of the "screened group". But since many spontaneous regression cases are included in the true positives, this method inflates the incidence of the "screened group", leading to underestimation of the effectiveness of the mass screening. When the false negatives are compared with the non-participants, the incidence of the cases in stage 4 among the latter is about 40% of that of the former, and the mortality is less than two-thirds. The percentage of spontaneous regression cases among the true positives is estimated to be about 40%. These results are better than those of the Japanese screening programs (targeting infants age 6 months), supporting the effectiveness of mass screening for neuroblastoma.