123I-mIBG scintigraphy in neuroblastoma: development of a SIOPEN semi-quantitative reporting ,method by an international panel

Abstract

PurposeA robust method is required to standardise objective reporting of diagnostic 123I-mIBG images in neuroblastoma. Prerequisites for an appropriate system are low inter- and intra-observer error and reproducibility across a broad disease spectrum. We present a new reporting method, developed and tested for SIOPEN by an international expert panel.MethodPatterns of abnormal skeletal 123I-mIBG uptake were defined and assigned numerical scores [0–6] based on disease extent within 12 body segments. Uptake intensity was excluded from the analysis. Data sets from 82 patients were scored independently by six experienced specialists as unblinded pairs (pre- and post-induction chemotherapy) and in random order as a blinded study. Response was defined as ≥50 % reduction in post induction score compared with baseline.ResultsIn total, 1968 image sets were reviewed individually. Response rates of 88 % and 82 % were recorded for patients with baseline skeletal scores ≤23 and 24-48 respectively, compared with 44 % response in patients with skeletal scores >48 (p = 0.02). Reducing the number of segments or extension scale had a small but statistically negative impact upon the number of responses detected. Intraclass correlation coefficients [ICCs] calculated for the unblinded and blinded study were 0.95 at diagnosis and 0.98 and 0.99 post-induction chemotherapy, respectively.ConclusionsThe SIOPEN mIBG score method is reproducible across the full spectrum of disease in high risk neuroblastoma. Numerical assessment of skeletal disease extent avoids subjective evaluation of uptake intensity. This robust approach provides a reliable means with which to examine the role of 123I mIBG scintigraphy as a prognostic indicator in neuroblastoma.

Norepinephrine Transporter as a Target for Imaging and Therapy

“…A modified Curie scoring system also includes soft-tissue lesions and is currently widely used in multicenter trials conducted by a children's oncology group (31). A similar scoring system, proposed by the International Society of Paediatric Oncology Europe Neuroblastoma, uses a 0-6 grading scale for skeletal and soft-tissue disease (32) and is recommended by an international panel for universal routine evaluation of MIBG scanning in high-risk neuroblastoma patients (33). MIBG scoring has high prognostic value at diagnosis and is predictive of overall survival and event-free survival in high-risk and stage IV neuroblastoma after other systemic treatments and in assessment of disease before myeloablative therapy (34).…”

Semi-quantitative scoring of skeletal metastases by 123I-mIBG scintigraphy in high-risk neuroblastoma

“…The recent article in the journal by Professor Valerie Lewington and colleagues [1] on the semi-quantitative scoring of the burden of bone and bone marrow metastases by iodine-123 meta iodobenzylguanidine ( 123 I-mIBG) scans is a welcome addition to the literature on the imaging of children with neuroblastoma.…”

“…In their recent paper, Lewington et al [1] have evaluated paired scans from diagnosis and after induction chemotherapy in 82 patients, of whom 62 had metastatic disease at presentation. With a response being defined as a 50% or greater reduction in the score, they found that those with the highest scores (>48/72) were significantly less likely to achieve a response to induction chemotherapy than those with lower scores at diagnosis.…”

“…68 Ga-DOTATATE PET [19,20], 18 F-fluorodopa PET [21,22] and labeled monoclonal antibody scans [23] may also be of value. Nonetheless, despite this embarrassment of riches in the techniques available for imaging neuroblastoma, 123 I-mIBG remains the gold standard, and semi-quantitative skeletal scoring as described by Lewington et al [1] should become the new norm.…”

“…The SIOPEN score, described by Lewington et al [1], divides the skeleton into 12 segments, giving each a score between 0 and 6, making a maximum possible score of 72. Soft tissue and primary tumor uptake is also noted.…”