The Association between Tumour Markers and Meta-iodobenzylguanidine Scans in South African Children with High-risk Neuroblastoma. Issue 8 (August 2021) - Van Heerden, J.
Abstract: Aims: Diagnostic and post-induction 123 I-meta-iodobenzylguanidine ( 123 I-mIBG) scans have prognostic significance in the treatment of neuroblastoma, but data from low- and middle-income countries are limited due to resource constraints. The aim of this study was to determine the association between neuroblastoma-associated tumour markers (lactate dehydrogenase [LDH], ferritin and MYCN amplification) and 123 I-mIBG scans (modified Curie scores and metastatic disease patterns) in predicting complete metastatic response rates (mCR) and overall survival. Materials and methods: Two hundred and ninety patients diagnosed with high-risk neuroblastoma in South Africa between January 2000 and May 2018 and a subanalysis of 78 patients with diagnostic 123 I-mIBG scans were included. Data collection included LDH, ferritin and MYCN amplification at diagnosis. Two nuclear physicians independently determined the modified Curie scores and pattern of distribution for each diagnostic and post-induction 123 I-mIBG scans with high inter-rater agreement ( r = 0.952) and reliability ( K = 0.805). The cut-off values for the diagnostic and post-induction modified Curie scores of ≥7.0 ( P = 0.026) and 3 ( P = 0.009), respectively, were generated. The association between the tumour markers and the modified Curie score of the 123 I-mIBG scans was determined using post-induction mCR and 2-year overall survival. Results: Diagnostic LDH ( P < 0.001), ferritin ( P < 0.001) and the diagnostic modified Curie scores ( P = 0.019) significantly predicted mCR. Only ferritin correlated with diagnostic modified Curie scores ( P = 0.003) but had a low correlation coefficient of 0.353. On multivariable analysis, the only significant covariate for 2-year overall survival at diagnosis was LDH <750 U/l ( P = 0.024). A post-induction chemotherapy modified Curie score ≤3.0 had a 2-year overall survival of 46.2% compared with 30.8% for a score >3.0 ( P = 0.484). Conclusion: LDH, ferritin and the diagnostic 123 I-mIBG scans significantly predicted mCR, but only LDH predicted 2-year overall survival. Ferritin and the modified Curie scores correlated with each other. MYCN amplification neither correlated with any aspect of the 123 I-mIBG scans nor significantly predicted mCR or 2-year overall survival. LDH and ferritin are therefore appropriate neuroblastoma tumour markers to be used in low- and middle-income countries with limited or no access to mIBG scans and/or MYCN amplification studies. Highlights: In South African children with high-risk neuroblastoma LDH, ferritin and the Modified Curie scores have predictive value. These prognostic factors predict post induction metastatic response rates (mCR) and 2-year overall survival (OS) rates. MYCN-amplification did not significantly predict mCR or OS. None of LDH, Ferritin or MYCN-amplification correlated with the Modified Curie scores.