Can neoadjuvant chemotherapy reduce the surgical risks for localized neuroblastoma patients with image-defined risk factors at the time of diagnosis?

Purpose To date, no detailed study of the changes in the image-defined risk factors (IDRFs) after neoadjuvant chemotherapy has been performed. The aim of this study was to investigate the effect of chemotherapy on IDRFs for stage L2 neuroblastomas. Methods Fifteen stage L2 patients treated by neoadjuvant chemotherapy were selected. Changes after chemotherapy in the number of positive IDRFs, tumor size and major surgical complications were evaluated. Results All IDRFs disappeared after chemotherapy in four patients (group A) and a reduction in the number of IDRFs, but not disappearance, after chemotherapy was observed in five patients (group B). No change in the number of IDRFs after chemotherapy was observed in six patients (group C). All tumors in groups A shrunk to <20 % of the pretreatment volume. Major surgical complications were observed in one of two, two of three and three of five patients who underwent tumor excision in groups A, B and C, respectively. Conclusions Only 27 % of the tumors with IDRFs became negative for IDRFs after chemotherapy. For negative IDRFs, tumors should shrink t <\20 % of the volume at the time of diagnosis. Stage L2 tumors may have a potential risk for surgery even after neoadjuvant chemotherapy.