Is there a future for neuroblastoma mass screening?

It is apparent that mass screening at the age of six months in Japan detects significant numbers of otherwise spontaneously regressing tumors. Nishi et al. estimated that at least 50% of tumors detected by screening with the HPLC method would otherwise regress spontaneously [31]. Considering that not all patients found by screening who were treated and survived required therapy to obtain that result, the proportion of spontaneously regressing NBLs would be even larger. Nobody can deny that screening at the age of six months detects some tumors that would otherwise be found clinically later on. Indeed, our data show that screening led to some decrease in incidence at the age of 3 years [10]. However, this study also showed that the tumors detected by screening would, if not picked up on screening, have grown very slowly over 3 years. That is, they were not rapidly progressing tumors. There is evidence showing that evolution from tumors with favorable biologic features to tumors with unfavorable ones is unlikely [32], while no convincing example of such evolution has been reported.