Stephen L. Gans overseas lecture. Mass screening for neuroblastoma in Japan: lessons learned and future directions.

BACKGROUND/PURPOSE: Since 1985, a nationwide mass screening program (MS) for neuroblastoma has been conducted for 6-month-old infants throughout Japan, resulting in the detection of more than 1,900 cases of neuroblastoma. The outcome of these patients has been excellent: more than 97% of them are alive. Yet, several reports suggest that the number of advanced-stage neuroblastoma patients over 1 year of age has not changed substantially. The current report focuses on the 15-year experience with MS of the Kyushu Pediatric Oncology Study Group.

METHODS: The clinical and biological features of neuroblastoms detected (n = 320) and not detected by MS (n = 245) were compared. Regional and national statistics for neuroblastoma before and after 1985 were analyzed using standard epidemiologic measures for the occurrence of disease.

RESULTS: The majority of the MS-positive cases were biologically favorable and had an excellent outcome. In contrast, the majority of non-MS patients in whom neuroblastoma later developed had advanced-stage, unfavorable-prognosis tumors. The overall mortality rate of neuroblastoma in the Kyushu area was not improved by MS.

CONCLUSIONS: The optimal time for screening is the point at which neuroblastomas regressing spontaneously can no longer be detected, but more aggressive disease can be found. A birth cohort study could determine the optimal timing for a second screening. Identification of other new prognostic factors may be required.