Michio Kaneko

PURPOSE: The International Neuroblastoma Risk Group (INRG) classification system was developed to establish a consensus approach for pretreatment risk stratification. Because the International Neuroblastoma Staging System (INSS) is a postsurgical staging system, a new clinical staging system was required for the INRG pretreatment risk classification system. METHODS: To stage patients before any treatment, the INRG Task Force, consisting of neuroblastoma experts from Australia/New Zealand, China, Europe, Japan, and North America, developed a new INRG staging system (INRGSS) based on clinical criteria and image-defined risk factors (IDRFs). To investigate the impact of IDRFs on outcome, survival analyses were performed on 661 European patients with INSS stages 1, 2, or 3 disease for whom IDRFs were known. RESULTS: In the INGRSS, locoregional tumors are staged L1 or L2 based on the absence or presence of one or more of 20 IDRFs, respectively. Metastatic tumors are defined as stage M, except for stage MS, in which metastases are confined to the skin, liver, and/or bone marrow in children younger than 18 months of age. Within the 661-patient cohort, IDRFs were present (ie, stage L2) in 21% of patients with stage 1, 45% of patients with stage 2, and 94% of patients with stage 3 disease. Patients with INRGSS stage L2 disease had significantly lower 5-year event-free survival than those with INRGSS stage L1 disease (78% +/- 4% v 90% +/- 3%; P = .0010). CONCLUSION: Use of the new staging (INRGSS) and risk classification (INRG) of neuroblastoma will greatly facilitate the comparison of risk-based clinical trials conducted in different regions of the world.

Neuroblastoma is an enigmatic disease entity; some tumors disappear spontaneously without any therapy, while others progress with a fatal outcome despite the implementation of maximal modern therapy. However, strong prognostic factors can accurately predict whether children have "good" or "bad" disease at diagnosis, and the clinical stage is currently the most significant and clinically relevant prognostic factor. Therefore, for an individual patient, proper staging is of paramount importance for risk assessment and selection of optimal treatment. In 2009, the International Neuroblastoma Risk Group (INRG) Project proposed a new staging system designed for tumor staging before any treatment, including surgery. Compared with the focus of the International Neuroblastoma Staging System, which is currently the most used, the focus has now shifted from surgicopathologic findings to imaging findings. The new INRG Staging System includes two stages of localized disease, which are dependent on whether image-defined risk factors (IDRFs) are or are not present. IDRFs are features detected with imaging at the time of diagnosis. The present consensus report was written by the INRG Imaging Committee to optimize imaging and staging and reduce interobserver variability. The rationales for using imaging methods (ultrasonography, magnetic resonance imaging, computed tomography, and scintigraphy), as well as technical guidelines, are described. Definitions of the terms recommended for assessing IDRFs are provided with examples. It is anticipated that the use of standardized nomenclature will contribute substantially to more uniform staging and thereby facilitate comparisons of clinical trials conducted in different parts of the world.

Hepatoblastoma (HBL) is the most common malignant liver tumor in young children. Recent reports have shown that the beta-catenin gene was frequently mutated or deleted in HBLS: To elucidate the role of beta-catenin abnormalities in HBLs, we searched for mutations of beta-catenin and APC as well as expression of the target genes, cyclin D1, c-myc, and fibronectin, in 68 primary HBLS: The mutation analysis revealed that 44 (65%) tumors carried missense mutations or deletions of beta-catenin, all of which were somatic and targeted to the exon 3 encoding the amino acid residues involved in its degradation. However, no loss of function mutation of the APC gene was detected by the yeast functional assay. Of interest, beta-catenin mutation was significantly correlated with overexpression of the target genes, cyclin D1 and fibronectin, but not with that of c-myc in HBLs as measured by quantitative real-time reverse transcription-PCR. The immunohistochemical studies in 15 HBLs demonstrated that the nuclear/cytoplasmic accumulation of beta-catenin was positive in 13 tumors, 9 of which had the deletion or mutation of the gene. The significant correlation between the beta-catenin gene abnormality and the positive staining of cyclin D1 was also confirmed. Furthermore, the nuclear accumulation of beta-catenin was strongly associated with the poorly differentiated tumor cell components as well as with the positive staining of cyclin D1 within the tumor. Thus, our present results suggested that the gain of function mutation of beta-catenin played a crucial role in the malignant progression of HBL in vivo.

One hundred nine newly treated patients with advanced neuroblastoma were entered in this study between January 1985 and May 1989. The eligible patients included infants younger than 12 months of age with Stage IVA disease (bone cortex, distant lymph node, and/or remote organ metastases) and patients aged 12 months or older with Stage III or IV disease (IVA plus IVB with tumor crossing the mid-line and with metastases confined to bone marrow, liver, and skin). The patients first received six cyclic course of intensive chemotherapy (regimen A1), consisting of cyclophosphamide (1200 mg/m2), vincristine (1.5 mg/m2), tetrahydropyranyl adriamycin (pyrarubicin; 40 mg/m2), and cisplatin (90 mg/m2). Original tumors and the regional lymph node metastases were removed some time during these first six cycles of chemotherapy. The patients were further divided into three groups. Patients in course 1 received alternating treatment by regimen B (cyclophosphamide and ACNU) and intensified regimen A1, and those in course 2 were treated with alternating administration of regimen C (cyclophosphamide and DTIC) and intensified A1. Patients in course 3 were treated with bone marrow transplantation (BMT) preceded by high-dose preconditioning chemotherapy. Survival rates were 77% in Stage III and 54% in Stage IV at 2 years, and 70% in Stage III and 45% in Stage IV at 3 years. The major toxicities encountered were bone marrow suppression with leukocyte counts down to 100/mm3, mild cystitis, and hearing impairment. The 2-year survival rate was 78% in 21 patients who underwent BMT when complete remission was achieved. We concluded that our intensive induction chemotherapy is of significant value in increasing the rate of complete response, and in widening the indications for and achieving improved results of treatment with BMT.