Journal of Clinical Oncology, Vol 11, 2211-2217, Copyright © 1993 by American Society of Clinical Oncology
Relation of tumor-cell ploidy to survival in children with medulloblastoma
AJ Gajjar, RL Heideman, EC Douglass, LE Kun, EH Kovnar, RA Sanford, DL Fairclough, D Ayers and AT Look
Department of Hematology-Oncology, St. Jude Children's Research Hospital, Memphis, TN 38105.
PURPOSE: To assess the value of tumor-cell ploidy as a predictor of
survival in medulloblastoma. PATIENTS AND METHODS: Ploidy determinations
were based on the flow-cytometric analysis of cellular DNA content in fresh
tumor specimens taken from 34 consecutively treated children with newly
diagnosed medulloblastoma. Patients were assigned a high or low risk of
failure depending on tumor size and invasiveness, and the presence or
absence of metastatic disease. Treatment consisted of radiotherapy, with or
without chemotherapy, according to institutional or cooperative group
protocols. RESULTS: Univariate analysis of candidate prognostic factors
showed that only tumor-cell ploidy and clinical risk group had a
statistically significant influence on survival. Patients with hyperdiploid
stem lines (n = 9) had significantly longer survival times (P = .04) than
did those with diploid lines (n = 20). The estimated 5-year survival
probabilities (+/- SE) for these two subgroups were 89% +/- 11% and 48% +/-
13%, respectively. Although clinical risk status (high v low) showed
essentially the same predictive strength as ploidy, the two features
identified largely nonoverlapping subgroups. Thus, within the clinical
high-risk group, it was possible to distinguish hyperdiploid patients whose
5-year survival rate (83% +/- 15%) was comparable to that of patients with
localized, low-risk tumors. CONCLUSION: This prospective study indicates
that both ploidy and clinical risk group are important prognostic factors
in medulloblastoma. Their combined use at diagnosis would distinguish
patients who require more aggressive therapeutic intervention (diploid,
clinical high-risk group) from those who could be expected to benefit most
from standard treatment.