Insights into infant neuroblastomas based on an analysis of neuroblastomas detected by mass screening at 6 months of age in Japan

Abstract

Mass screening (MS) for neuroblastoma (NB) at 6 months of age in Japan was discontinued in 2004. The authors have previously reported that the majority of the NB detected by MS showed a favorable prognosis. This study aimed to provide insights into infant NB by assessing the details of clinical courses in patients treated with standard regimens and the biological features of such cases using highly sensitive methods at one institution in Japan. In 76 NBs detected by MS, the clinical features and MYCN amplification, 1p deletion, I7q gain, the expression levels of TrkA using FISH and the quantitative PCR were analysed. Of these 76 children, 97% are still alive, whereas 2 children died from other diseases. Three patients experienced a recurrence after complete remission (CR), and 2 patients demonstrated refractory disease since the initial diagnosis. Two of the 3 NB patients with recurrence achieved a 2nd CR, whereas one case still has multiple active disease. Regarding the findings of highly sensitive biologic analyses, 5/74 (7%) showed MYCN amplification, 2/24 (8%) had a 1p deletion, 3/33 (9%) cases had a 17q gain, 5/59 (10%) cases had diploidy, 1/25 (4%) cases had a low expression of TrkA, and 2/76 (3%) had an unfavorable histology. Of the 76 NB, 13 tumors (17%) had one or more unfavorable factors (UF). Of the 5 refractory NB, 1 case had 3 UF, 1 case had 2 UF, 1 case had 1 UF, and 2 cases had no UF. It is concluded that 17% of the NB detected by MS had one or more UF and might have a higher risk of recurrence than the patients without UF. It may therefore be most important to analyze biologically prognostic factors using highly sensitive methods in NB, followed by immediate surgical intervention.