What is the significance of negative MIBG scan and urine catecholamines in children with neural crest tumors?

Abstract

8553 Background: The clinical presentation of ganglioneuroblastoma (GNB) or ganglioneuroma (GN) is often very similar to neuroblastoma (NB). Although MIBG scan and urine catecholamines level are both very sensitive investigations in the diagnosis of NB, the results profile of these 2 tests in GNB or GN is less clear. Methods: Retrospective chart review on 82 children diagnosed with neural crest tumor at the Royal Alexandra Hospital for Children between 1991 and 1999. Results: 75 patients had informative MIBG and urine homovanillic acid (HVA)/vanillylmandelic acid (VMA) results at diagnosis. 65 were histologically classified as NB, 4 GNB and 6 GN. There were 6 Stage IVs, 32 Stage IV and 37 Stage I-III patients. All GNB/GN were localized tumors. 94% of NB were MIBG positive versus 60% of GNB/GN (P<0.01). Elevated levels of HVA (>19mmol/mol creatinine) and/or VMA (>15mmol/mol creatinine) were found in 91% of NB versus 20% of GNB/GN (P<0.0001). 57 patients were MIBG positive with high HVA/VMA (Group1: 56 NB, 1 GN). 14 patients were either MIBG positive or had high HVA/VMA (Group2: 8 NB, 4 GNB, 2 GN). 4 patients were both MIBG and urine negative (Group3: 1 NB, 3 GN). All 38 metastatic NB were in Group1, which consisted of 23% localized tumors. In comparison, Group 2 & 3 consisted of localized tumors only and 50% were GNB/GN. It was 6.5 times more likely for a Group 2 or 3 tumor to be a GNB/GN than a NB (P<0.0001). 5-year OS was inferior for Group 1 compared with Group 2 & 3 (48% vs 93%; P=0.01) with a median follow-up of 36 months. The 1 death in Group 3 was a NB. Conclusions: Non-secretory and MIBG negative tumors comprised 5% of all neural crest tumors, 1.5% of NB and 30% of GNB/GN. Neural crest tumors, which were MIBG and/or urine negative, were significantly more likely to be non-metastatic NB or a GNB/GN and had an excellent prognosis. No significant financial relationships to disclose.