A new staging method versus TNM staging in children with posterior fossa primitive neuroectodermal tumor (medulloblastoma).

Prognostic factors were evaluated in 30 children with primitive neuroectodermal tumors of the posterior fossa (classical medulloblastoma or differentiated medulloblastoma). The preoperative TNM (Tumor, Node, Metastasis) staging system has been applied to estimate prognosis of patients with central nervous system tumors, but this system was not applicable in assessing the postoperative status of the tumor. To fill this need, a postoperative staging system was developed known as MAPS (Metastasis, Age, Pathology, Surgery), and in this report its efficacy is compared with that of the TNM system. The predictive values of MAPS staging in these 30 children were better than those obtained using the TNM method (MAPS r2 = -0.90; TNM r2 = 0.73; P less than 0.05).