34.01 Impact of Functional PET Imaging on the Surgical Treatment of Neuroblastoma

Posted on January 18, 2018

W. Hsu1, W. Hsu1  1National Taiwan University Hospital,Division Of Pediatric Surgery, Department Of Surgery,Taipei, ., Taiwan

Introduction:

Gross total resection (GTR) of neuroblastoma (NB) could be predicted by imaging-defined risk factors (IDRFs) on CT/MR images but might also be confounded by other biological features. This study aims to investigate the complementary role of positron emission tomography (PET) scans in predicting GTR of NB in addition to IDRFs.

Methods:

From 2007 to 2014, diagnostic PET scans with 18F-fluorodeoxyglucose (FDG) and 18F-fluoro-dihydroxyphenylalanine (FDOPA) were performed in 42 children with NB at National Taiwan University Hospital, Taipei, Taiwan. The extent of tumor resections was correlated with clinical features and imaging findings. 

Results:

Among 42 NB patients with diagnostic FDG and FDOPA PET images (median age, 2.0 [0.5–4.9] years; male:female, 28:14), 8 patients had their primary tumors responded completely to induction chemotherapy and were excluded from the analysis. For the rest 34 patients, 27 (79.4%) could achieve GTR of the primary tumor including 9 patients (26.5%) at the first operation and 18 patients (52.9%) at the best subsequent operation(s) , while the other 7 patients (20.6%) only had partial resection. Based on the primary tumors’ maximal standard uptake value (SUVmax) on PET scans, we found that the SUVmax ratio between FDG and FDOPA (G:D) was positively correlated with Hexokinase 2 (HK2; P = 0.002) gene expression but negatively with Dopa decarboxylase (DDC; P = 0.03) gene expression levels. Tumors with higher-than-median G:D ratio (G:D ≥ 1.4), indicating a “glycolytic” phenotype with less catecholaminergic differentiation, was also correlated with poor-risk genomic types (P < 0.001) and a lower probability of GTR (56% vs. 100%; P = 0.007). Using the G:D ratio to predict GTR also complemented the anatomical IDRF from CT/MRI (GTR rate, 46% vs. 100% among 20 patients with IDRF; P = 0.04). Yet, GTR or IDRF per se was not associated with survival outcome.

Conclusion:

NB tumors with higher FDG uptake and lower FDOPA uptake at diagnosis were associated with a less likelihood of GTR. The incorporation of functional PET imaging may help to develop a more tailored, risk-directed surgical strategy for NB patients.