Primitive neuroectodermal tumors/
medulloblastoma (
PNET/MB) are the most common
posterior fossa tumors in childhood. Despite surgery and
radiation therapy, 40% to 50% of children with
PNET/MB will have recurrent disease. Various chemotherapeutic agents are transiently effective in recurrent
PNET/MB, but long-lasting responses are rarely attainable. To increase the rate and duration of response in children with recurrent
PNET/MB, the authors treated seven patients (ages 2-18 years; median, 10 years) with
lomustine (
CCNU) (100 mg/m2),
cisplatin (CPDD) (90 mg/m2) and
vincristine (VCR) (1.5 mg/m2; maximum, 2 mg) in a 6-week cycle for a maximum of eight cycles. Six of six evaluable patients responded to
chemotherapy. Four patients had a complete response; three with complete disappearance of
tumor by imaging studies; and one with eradication of extraneural disease for a median of 24 months from relapse (13-29 months). Overall disease-free survival was 18.5 months. All six patients have subsequently died of recurrent
tumor. Major toxicities consisted of reversible bone marrow suppression (six of six),
high frequency hearing loss (six of six) and decreased renal function (three of six). All patients required dosage modification for toxicity. A regimen of
CCNU, VCR, and CPDD is effective
therapy in children with relapsed
PNET/MB and can produce relatively long-term disease control with good quality of life. Further investigation into the efficacy of this combination as
adjuvant chemotherapy in newly diagnosed high-risk
PNET/MB is now being performed.