Frequency, Risk-factors and Survival of Children with Atypical Teratoid Rhabdoid Tumors (AT/RT) of the CNS Diagnosed Between 1988 and 2004, and Registered to the German HIT Database

Purpose: To analyze the frequency, prognostic factors, and outcome of children with atypical teratoid/rhabdoid tumors (AT/RT), a rare and highly malignant embryonal brain tumor.

Materials And Methods: Clinical data of patients diagnosed between 1988 and 2004 with AT/RT who were registered to the German HIT trial center, were correlated with outcome. Patient numbers for AT/RT were compared to numbers for primitive neuroectodermal tumors and medulloblastomas (PNET/MB) registered to the population-based HIT trials.

Results: We identified 56 patients with the centrally confirmed histopathological diagnosis of AT/RT with a median age of 1.2 years (range, 0.1-14.0 years). The AT/RT:PNET/MB ratio was 1:12.2 for all children, and 1:1.5 for children younger than 1 year at diagnosis. Three-year overall survival (OS) and event-free survival (EFS) for all patients were 22% and 13%, respectively. Eight patients (14%) are considered long-term event-free survivors (follow-up 1.4-10.6 years). By univariable analyses, younger age, metastatic disease, infratentorial location, and less than complete remission at the end of chemotherapy were identified as negative influencing factors for OS. By multivariable analyses, younger age (OS, EFS) and metastatic disease (OS) were identified as independent risk factors.

Conclusion: The incidence of AT/RT in children below 1 year is higher than previously reported. A subset of patients with favorable clinical risk factors profits from intensive multimodal treatment. Prospective clinical and biological studies are needed to further define prognostic factors and optimize therapy.