High-dose Thiotepa as Consolidation Therapy With Autologous Hematopoietic Stem Cell Transplantation for High-risk Ewing Family Tumors: Single-institution Experience.

High-dose therapy (HDTx) with autologous stem cell rescue has been widely applied in very-poor-risk pediatric solid tumors. Promising data have become available with the use of high-dose busulfan, whereas high-dose (HD) thiotepa is less commonly used. We report retrospectively our single-institution experience from 1986 to 2012 of single and tandem HDTx with special emphasis on HD-thiotepa as the backbone of HD regimen in Ewing family tumors, including all 24 patients in the Helsinki University Hospital referral area in population-based fashion (Ewing sarcoma 9, Askin tumor 9, peripheral neuroectodermal tumor 6). The 10-year overall survival for the entire cohort was 0.73±0.01. Thirteen out of the 24 underwent HDTx (10 single, 3 tandem). The HDTx regimen consisted of HD-thiotepa (900 mg/m), VP16, and carboplatin. Additional HD-melphalan and total body irradiation were used in the tandem regimens. There was no toxic mortality. The 5-year event-free survival was 0.73±0.16 for high-risk cases transplanted in 1CR. In the relapse group, 1 out of the 3 survived. Radiotherapy to axial sites was given safely in combination with HD-thiotepa in all 3 patients. Thiotepa-based HDTx approach resulted in an encouraging outcome without toxic mortality for high-risk patients. HD-thiotepa merits further studies in larger controlled series.