[Scintigraphic diagnosis of neuroblastoma using meta-iodobenzylguanidine]

Comparison of diagnosing and staging accuracy of PET (CT) and MIBG on patients with neuroblastoma: Systemic review and meta-analysis

To perform a systemic review and meta-analysis of the diagnostic accuracy of PET (CT) and metaiodobenzylguanidine (MIBG) for diagnosing neuroblastoma (NB), electronic databases were searched as well as relevant references and conference proceedings. The diagnostic accuracy of MIBG and PET (CT) was calculated for NB, primary NB, and relapse/metastasis of NB based on their sensitivity, specificity, and area under the summary receiver operating characteristic curve (AUSROC) in terms of per-lesion and per-patient data. A total of 40 eligible studies comprising 1134 patients with 939 NB lesions were considered for the meta-analysis. For the staging of NB, the per-lesion AUSROC value of MIBG was lower than that of PET (CT) [0.8064±0.0414 vs. 0.9366±0.0166 (P<0.05)]. The per-patient AUSROC value of MIBG and PET (CT) for the diagnosis of NB was 0.8771±0.0230 and 0.6851±0.2111, respectively. The summary sensitivity for MIBG and PET (CT) was 0.79 and 0.89, respectively. The summary specificity for MIBG and PET (CT) was 0.84 and 0.71, respectively. PET (CT) showed higher per-lesion accuracy than MIBG and might be the preferred modality for the staging of NB. On the other hand, MIBG has a comparable diagnosing performance with PET (CT) in per-patient analysis but shows a better specificity.

Uptake and release of iodine-labelled m-iodobenzylguanidine in a neuroblastoma cell culture system and its importance in neuroblastoma therapy

A neuroblastoma cell line was established from bone marrow of a patient in stage IV of the disease and used as a model system in order to elaborate experimental data of importance in neuroblastoma therapy, such as cell-drug interactions, the mode of uptake and conditions for storage and release. m-Iodo benzylguanidine (MIBG) is rapidly taken up from culture medium, giving high concentrations of cell-bound radioactivity reaching a maximum level 4 h after the addition of the compound. A removal of the radiopharmacon from the culture medium causes a dramatic loss of cell-associated radioactivity, suggesting that neuroblastoma cells are not able to retain MIBG in a drug-free environment. Replacement of labelled by unlabelled MIBG prevents a similar release and maintains high levels of cellular radioactivity. Variations of cell culture conditions only result in minor changes of uptake rates, whereas a pretreatment with drugs used in neuroblastoma chemotherapy harms the cells extensively: even after a short-term exposure the cells lose the capacity for MIGB uptake and fail to recover within a long period of incubation in growth medium. The importance of our results is discussed, leading to the following suggestions: 1. The performance of radiotherapy with labelled MIBG is recommended prior to the chemotherapy protocols. 2. Therapeutically effective radioactivity in tumor tissues may be maintained by the additional infusion of unlabelled MIGB.