Metastatic progression in infants diagnosed with stage 4S neuroblastoma. A study of the Italian Neuroblastoma Registry

Purpose: Stage 4S neuroblastoma, a tumor affecting infants, is characterized by the capacity to regress spontaneously and high cure rate. About a third of these infants undergo tumor progression requiring antitumor treatment and 10-15% eventually die. In case of metastatic progression, it may occur either at 4S sites (mainly liver) or sites characterizing stage 4 (mainly bone). Aim of this study was to estimate incidence, presenting features and outcome of infants who progressed to stage 4S or stage 4 sites. Patients: Of 280 Italian infants diagnosed with stage 4S neuroblastoma between 1979 and 2013 and registered in the Italian Neuroblastoma Registry, 268 were evaluable for this study, of whom 57 developed metastatic progression. Results: Progression to stage 4S sites occurred in 29/268 infants (10.8%) (Group A) and to stage 4 in 28/268 (10.4%) (Group B). No significant difference was observed between the two groups at the time of diagnosis. At the time of progression, Group A infants were younger (7.3 vs 14.4 months, P =.001) and had a shorter interval from diagnosis to progression (3.8 vs 9.6 months, P =.001). Survival after progression was worse for Group B infants (45% vs 69%, P =.058) and was associated with age at diagnosis lower than 2 months (P =.005) and adrenal primary tumor site (P =.008). Survival rates increased for both groups along the study period. Conclusions: Infants who progressed to stage 4 did worse, possibly in relation to older age at progression and longer interval between diagnosis and progression. Large prospective studies of these patients may lead to more effective treatments.