Collection and use of peripheral blood stem cells in young children with refractory solid tumors

Abstract

Fifteen children 4 years of age or under (8–46 months), weight 7.8 to 17 kg, underwent 44 peripheral blood stem cell (PBSC) collections. Diagnoses included PNET/ medulloblastoma (five), neuroblastoma (five), and others (five). PBSCs were collected following G-CSF/GM-CSF or chemotherapy plus G-CSF/GM-CSF mobilization. All PBSC collections were well tolerated. The average yield per collection was 6.80 × 10⁸ mononuclear cells/kg (1.1–30 × 10⁸/kg) or 57.60 × 10⁶ CD34⁺/kg (1.37 to 480 × 10⁶/kg). Eight patients underwent stem cell transplantation following myeloablative chemotherapy. Six of the eight children who received PBSC following myeloablative therapy also received autologous bone marrow (0.7 to 3.6 × 10⁸ MNC/kg). One heavily pretreated patient experienced delayed hematologic reconstitution, while the remaining seven patients had a median ANC recovery to >0.5 × 10³/μ l by day +10 (9–11 days) and platelets >50 × 10³/μ l by day +15 (12–17 days). Seven patients received PBSCs following repetitive submyeloablative chemotherapy (ICE: ifosfamide 1.8 g/m²/day, etoposide 100 mg/m²/day × 5, carboplatin 400 mg/m²/day × 2) or other similar combination chemotherapy. Median days to recover ANC ⩾1 × 10³/μ l and platelets ⩾100 × 10³/μ l in children receiving ICE + PBSCs were 10 and 14 days, respectively, compared with 16 and 22 days in children receiving ICE + G-CSF in historical controls. In conclusion, collection and use of PBSCs to support either myeloablative chemotherapy or multicycle submyeloablative chemotherapy is well tolerated and may enhance hematological recovery in young children and infants.