Treatment of recurrent central nervous system primitive neuroectodermal tumours in children and adolescents: results of a Children's Cancer and Leukaemia Group study.

BACKGROUND: The treatment of previously irradiated patients with recurrent central nervous system primitive neuroectodermal tumours (PNETs) is a considerable challenge. A study was undertaken to attempt to improve the outcome for such patients using a high dose chemotherapy (HDCT) based strategy.
METHODS: Between 2000 and 2007, 40 patients with relapsed medulloblastoma (MB) and 5 with relapsed supratentorial PNETs (StPNETs) were accrued. All but one had received prior craniospinal radiotherapy. Patients were initially treated with cyclophosphamide (4 g/m(2)) together with surgery or local radiotherapy where appropriate. If complete or near complete remission was achieved, the patient proceeded to receive two sequential courses of HDCT with stem cell rescue. The first course consisted of thiotepa (900 mg/m(2)) and the second carboplatin (AUC 21).
RESULTS: All five patients with StPNET died of tumour progression with a median OS of 0.4 years. Nineteen of the 40 patients with relapsed MB underwent surgery. Radiotherapy was administered to eight patients. All patients received at least one course of cyclophosphamide. Only 22 MB patients progressed to the HDCT phase; 10 patients received thiotepa only and 12 thiotepa and carboplatin. At a median follow-up of 7.4 years (Range 2.8-8.2 years), only three MB patients are still alive, one following a further relapse. Three and 5 year OS was 22.0% and 8.2%, respectively and 3 and 5 year EFS was 14.6% and 8.7%, respectively.
CONCLUSION: This national study based on a strategy including a particular tandem HDCT regimen showed no benefit for previously irradiated patients with relapsed StPNET and very limited benefit for patients with relapsed medulloblastoma.