International neuroblastoma pathology classification adds independent prognostic information beyond the prognostic contribution of age.

Age has been used as a prognostic factor for patients with peripheral neuroblastic tumours (pNTs). The latest analysis disclosed a cut-off around 18 months for the optimal prognostic distinction. The International Neuroblastoma Pathology Classification (INPC) distinguishes favourable and unfavourable histology based on the age-appropriate evaluation of histologic indicators (grade of neuroblastic differentiation, mitosis-karyorrhexis index) in the categories of neuroblastoma and ganglioneuroblastoma, nodular. This study showed that age tested by using 3 different cut-offs (12, 18, 24 months) was prognostically significant. INPC remained prognostically significant regardless of the age group to which it was applied. Prognostic effects of age and histologic indicators were independently significant, i.e., age had prognostic ability beyond that of histologic indicators, and histologic indicators had prognostic ability beyond that of age. Due to the fact that INPC incorporated age factor (18, 60 months) in the system, it served better than age by itself for prognostic distinction of pNT patients.