Nine patients (all MYCN-non-amplified) remained progression-free through 43+ to 74+ (median 54+) months from study entry, including the sole patient to show a complete response and eight patients who had persistence of abnormal <sup>123</sup> I-metaiodobenzylguanidine skeletal uptake but never developedprogressive disease.
Patients with MYCN(-), high-risk neuroblastoma display a broad, continuous spectrum with regard to response and outcome, whereas MYCN(+) patients either have an excellent response to induction associated with good long-term outcome or develop early progressive disease with a poor outcome.
According to initial reports, stage 4 neuroblastoma patients with amplification of the MYCN proto-oncogene developed progressive disease within 8 months.