I-131 mIBG Scintigraphy Curie Versus SIOPEN Scoring: Prognostic Value in Stage 4 Neuroblastoma

Objective: I-131 mIBG scan semi-quantitative analysis with modified Curie and the International Society of Pediatric Oncology Europe Neuroblastoma (SIOPEN) scoring systems is helpful in the evaluation of disease extent and has prognostic impact in stage 4 neuroblastoma.

Methods: Retrospective, cross-sectional analysis of baseline I-131 mIBG scans in 21 patients with stage 4 or 4S neuroblastoma diagnosed between January 2007 and December 2015. All scans were assessed for Curie and SIOPEN scores. Distribution of scores was evaluated for risk factors i.e. age at diagnosis (>18 months) and early relapse (within 12 months). A curie score <2 and SIOPEN score <4 at diagnosis were correlated with event-free survival (EFS) and overall survival (OS).

Results: The data set comprised of 12 (57%) males and 9 (43%) females. Patients with age >18 months (n=9) at diagnosis or early relapse (n=9) had higher Curie [mean 5+7.5 standard deviation (SD), p=0.004] and SIOPEN (mean 5.2+10.8 SD, p=0.02) scores. Patients with a Curie score <2 and a SIOPEN score of <4 had better EFS and OS than patients with higher scores. Curie: 5-year EFS=Curie <2 (79%) versus Curie >2 (33%) (p=0.03); 5-year OS=Curie <2 (56%) versus Curie >2 (36%) (p=0.01). SIOPEN: 5-year EFS=SIOPEN <4 (70%) versus SIOPEN >4 (17%) (p=0.002); 5-year OS=SIOPEN <4 (58%) versus SIOPEN >4 (17%) (p=0.04). There was no statistically significant difference between the two scoring systems in terms of survival predictive value (Hazard ratio 2.38, 95% CI: 0.33-16.9, p=0.38).

Conclusion: I-131 mIBG Curie and SIOPEN scores have prognostication value in stage 4 neuroblastoma and should be routinely applied. Higher scores predict unfavorable prognosis.