Objective: 1. To evaluate the relative efficacy of In-111 pentetreotide and 1-131 radioiodinated meta-idobenzyl guanidine (MIBG) for detection of primary and metastatic neuroblastoma. 2. To assess the prognostic value of In-111 pentetreotide uptake.
Methods and materials: Seven In-111 pentetreotide and seven I-131 MIBG scans were obtained in six patients with stage IV neuroblastoma and 1 with stage III ganglioneuroblastoma. Three scans were obtained at initial staging and four were obtained during therapy. Correlation was made with concomitant computed tomography scans, bone scans, N-myc oncogene amplification, and clinical outcome.
Results: Primary tumor was present in six patients and had been resected in 1. In-111 pentetreotide uptake was seen in two of six primary tumors, I-131 MIBG scan was positive in five of six. In-111 pentetreotide scan was positive in two of four patients with bone metastases, I-131 MIBG scan was positive in three of four. Both showed liver metastases in one patient and did not show bone marrow metastases in another. Overall sensitivity for primary or metastatic disease was 57% (four of seven) for In-111 pentetreotide and 86% (six of seven) for MIBG. Correlation between N-myc oncogene and In-111 pentetreotide uptake was seen in four of seven patients. In-111 pentetreotide uptake correlated with the clinical outcome in six patients with more than 1 year follow-up. Two patients with negative In-111 pentetreotide scans had unfavorable outcome. One patient died, and the other had local recurrence 15 months after diagnosis. Four patients with a positive scan are alive without disease on follow-up at 13-31 months after diagnosis.
Conclusion: In-111 pentetreotide scintigraphy is less sensitive than I-131 MIBG for detecting active neuroblastoma. In-111 pentetreotide uptake on scintigraphy may correlate with the prognosis. However, a larger series of patients is needed for further evaluation.