The prognostic impact of functional imaging with 123I-mIBG in patients with stage 4 neuroblastoma >1 year of age on a high-risk treatment protocol: Results of the German Neuroblastoma Trial NB97

Abstract

Aim/Purpose 123I-meta-iodobenzylguanidine ( 123I-mIBG) scintigraphy is well established for staging and evaluation of response in children with high-risk neuroblastoma but its prognostic value in highly intensive first-line treatment protocols is uncertain. The presence of any 123I-mIBG positive tumour tissue was correlated with event-free survival (EFS) and overall survival (OS). Patients and methods The prognostic impact of residual 123I-mIBG uptake into the primary tumour and metastases for predicting outcome in 113 stage 4 neuroblastoma patients >1 year of the German Neuroblastoma Trial NB97 was assessed using a univariate log-rank test and multivariate Cox regression analysis. Results All patients had 123I-mIBG positive disease at initial staging. After four courses of induction chemotherapy, 71% of patients were still 123I-mIBG positive for the primary tumour and 61% for metastases. After six courses, 39% of patients had 123I-mIBG uptake by the primary tumour and 45% residual 123I-mIBG positive metastatic disease. The 123I-mIBG status of the primary tumour site had no bearing on outcome. Residual 123I-mIBG positive metastatic disease after four (3-y-EFS 25.7 ± 5.3% versus 55.9 ± 7.6%, p = 0.009; 3-y-OS 49.8 ± 6.1% versus 65.0 ± 7.3%; p = 0.021) and after six chemotherapy cycles (3-y-EFS 27.5 ± 6.2% versus 47.4 ± 6.4%, p = 0.011; 3-y-OS 50.5 ± 7.1% vs 60.0 ± 6.4%, p = 0.031) was associated with poor outcome. Conclusion Functional imaging with 123I-mIBG scintigraphy can identify poor responders with any persistent metastatic 123I-mIBG uptake who are at a high risk of disease relapse. 123I-mIBG response of the primary tumour site had no bearing on outcome.