High dose alkylator therapy for extracranial malignant rhabdoid tumors in children.
BACKGROUND
Extracranial malignant rhabdoid tumor (MRT) is a rare pediatric cancer with a poor prognosis. The kidney is the most common site. Isolated reports have shown improvements in patient survival, but no specific treatment regimen has shown efficacy over others.


PROCEDURE
Retrospective review of patients diagnosed with extracranial MRT at Children's Hospital Los Angeles between 1983 and 2012.


RESULTS
The median age at presentation for the 21 patients was 13 months (range, 0-108 months). Ten patients had renal primary tumors. The median time to progression was 4 months (range, 0.4-7 months). The 5-year event free survival (EFS) and overall survival (OS) of the entire cohort was 38 ± 10.6%. After 2002, patients diagnosed with extracranial MRT were administered a chemotherapy regimen of vincristine, doxorubicin and high dose cyclophosphamide (VDC). The OS for the patients diagnosed before and after 2002 were 20 ± 12% and 54 ± 15%, respectively. Of the 13 patients who received VDC containing regimen, eight patients achieved a complete radiological remission; five of these patients are long-term survivors. Four patients who received autologous bone marrow transplantation were alive at last follow-up. All patients with unresectable primary tumors died. Patients who had disease progression or relapse did not survive.


CONCLUSIONS
Patients with extracranial MRT have a poor prognosis. Treatment with high dose alkylator therapy followed by consolidation with high dose chemotherapy and autologous bone marrow transplant for those patients in radiographic complete remission appears to have a beneficial effect on survival.