Evaluation of the Shimada classification in advanced neuroblastoma with a special reference to the mitosis-karyorrhexis index: a report from the Childrens Cancer Study Group.

Abstract

Histopathology of 46 cases of Stage III and Stage IV neuroblastoma collected at the Childrens Cancer Study Group Pathology Center was reviewed independently by two pathologists to formulate essential steps in the determination of the mitosis-karyorrhexis index (MKI), to assess interobserver concordance, and to evaluate prognostic significance of the Shimada classification system. "Absolute" agreement (obtained after the review by both pathologists) or "consensus" agreement (obtained after the second review of cases with initial discrepancy) was achieved with respect to category of MKI in 93% of 40 stroma-poor neuroblastomas and prognostic subgrouping in 98% of the total cases. This classification system distinguished favorable from unfavorable prognostic subgroups significantly (P = 0.0002), and the prognostic effects were largely unaltered when adjusted for age and stage of the patients (P = 0.0005) in this series.