Proposal and Assessment of Japanese Tumor Node Metastasis Postsurgical Histopathological Staging System for Neuroblastoma Based on an Analysis of 495 Cases

In 1971, the Japanese Society of Pediatric Surgeons' Committee on Malignancies proposed new criteria for neuroblastoma staging. It was fundamentally, based on the system of Evans et al. described in 1971. The main difference was the separation of stage IV disease into stages IV-A, with metastases to bone, orbita, distant lymph nodes and viscera other than liver, IV-B, the primary tumor extending over the midline and with metastases to bone marrow, liver and skin, and IV-S, which was the same as that of Evans et al. The new criteria did not include the resectability of the primary tumor, assessment of regional lymph node involvement or any other disease assessment resulting from therapeutic intervention. For the purpose of international usage, the Japanese system has been newly formulated and proposed as the Japanese Tumor Node Metastasis (TNM) Postsurgical Histopathological Classification for Neuroblastoma. In the present report, 495 neuroblastomas, registered between 1970 and 1985, were analyzed retrospectively according to the International Union Against Cancer (UICC) TNM classification and the proposed Japanese TNM system. The analyses suggested that the Japanese system reflected both the extent of tumor invasion and its biological neuroblastoma characteristics better than the UICC TNM classification based on statistical analysis.