Atypical Neuroblastoma With Absent Urinary Catecholamine Excretion and ¹²³ImIBG Avidity Are of Favorable Outcome: A...

In neuroblastoma (NB), urinary catecholamine excretion and ¹²³ImIBG avidity-depending on tumor enzymatic activity and norepinephrine transporter expression, respectively-are diagnostic standards. The prognostic impact of atypical NB, without urinary catecholamine excretion and/or ¹²³ImIBG avidity, remains to be determined. We sought to determine the frequency and prognosis of atypical NB and investigate the significance of catecholamine profiles and ¹²³ImIBG avidity at diagnosis.

From 2000 to 2020, 275 children with NB, aged 0-20 years at diagnosis, treated at Institut Curie, France, were retrospectively analyzed.

Overall, 24% of NB had atypical features (n = 67/275). Lower INRG stages L1/L2 were more frequent in atypical NB, 66% versus 28% (n = 44/67 vs. 59/208), with less INRG Stage M than in typical NB, 25% versus 61% (n = 17/67 vs. 126/208), p < 0.001. Atypical tumors more frequently harbored favorable molecular features with less frequent MYCN amplification, 12% (n = 8/64) versus 29% (n = 58/201), p < 0.01, and fewer cases with segmental chromosomal alterations, 30% (n = 13/44) versus 60% (n = 69/115), p < 0.05. Event-free survival (EFS) and overall survival (OS) were better in atypical than typical NB (5-year EFS: 77% ± 5% vs. 50% ± 4% and OS 87% ± 4% vs. 65% ± 4%, p < 0.001). However, in multivariate analysis, atypical features in NB were not significant independent markers of prognosis.

Atypical NB constitute a subgroup of interest for biomolecular analyses, including transcriptomics, which might provide further insights into disease-associated molecular features and our understanding of NB development.