Factors affecting event free survival (EFS) after high dose chemotherapy with stem cell rescue (HDC/SCR) in children with brain tumors

Abstract

9057 Background: HDC/SCR is a novel approach for treatment of children with brain tumors. Despite several studies suggesting results are better in children with primitive neural ectodermal tumors (PNET) or medulloblastoma (MB), it is controversial whether other factors can predict outcome. Methods: We retrospectively analyzed data from 53 patients who underwent HDC/SCR for brain tumors at Children Hospital Los Angeles between June 1992 and June 2005. Patients were aged 4 months to 15.8 years at diagnosis and 9 months to 18.1 years at transplant. In all cases the conditioning regimen included thiotepa and/or etoposide and/or carboplatin. The variables considered were age at diagnosis, histology, extent of disease, conditioning regimen, radiation therapy, stem cell type and timing of transplant. Results: Diagnoses included 33 PNET/MB, 8 high-grade gliomas, 5 ependymomas, 3 germinomas, 2 choroid plexus carcinomas and 2 rhabdoid tumors. Overall event free survival at 36 months was 53±9.1% in PNET/MB and 40±15.5% in tumors with other histology. Variables associated with better EFS in PNET/MB were no prior progression (p=0.00094), no spread into bone marrow (p=1.2 E-10) and age less than 3 years at diagnosis (p=0.046). There was a trend toward improved outcome if there was gross total resection of the tumor (p=0.11). Patients with PNET transplanted before progression had better EFS if they had localized disease at diagnosis (p=0.00024), and if gross total surgical resection was accomplished (p=0.11). Patients with PNET/MB transplanted after progression had better EFS if there was no spread of disease into blood or bone marrow (p=0.00023), if they were male (p=0.053), had localized disease at relapse (p=0.12) and if radiotherapy was given after transplant (p=0.053). In patients with tumors of other histology, the only variable associated with prolonged EFS was gross total resection (p=0.026). Conclusions: Children most likely to benefit from HDC/SCR for brain tumors are those less than 3 years old who are newly diagnosed with PNET that is locally confined, and those with a non-PNET diagnosis who have gross total resection of tumor. No significant financial relationships to disclose.