Reduction from seven to five cycles of intensive induction chemotherapy in children with high-risk neuroblastoma

Purpose We previously reported a high response rate with a dose-intensive chemotherapy regimen in 24 children with high-risk neuroblastoma (NB). We now describe similar results with changes that reduce toxicity (fewer cycles, less vincristine, use of granulocyte colony-stimulating factor). Patients and Methods Eighty-seven consecutive newly diagnosed children with high-risk NB underwent induction that initially had seven cycles (57 patients) but was later limited to five (30 patients). Cycles 1, 2, 4, and 6 used cyclophosphamide (140 mg/kg)/doxorubicin (75 mg/m(2))/vincristine (0.15 mg/kg in the first 27 patients, 0.067 mg/kg subsequently). Cycles 3, 5, and 7 used cisplatin (200 m/m(2))/etoposide (600 mg/m(2)). Tumor resection followed a minimum of three cycles. The induction was eventually modified to include anti-G(D2) immunotherapy after each of the last three cycles (38 patients). Results Bone marrow disease resolved in 70 (91%) of 77 patients and was not detected pre- and postinduction in 10 patients. After cycle 3 or 4, 86% of primary tumors were more than 50% smaller. Postinduction metaiodobenzylguanidine scans showed normal radiotracer distribution in metastatic sites in 74 (87%) of 85 patients. Overall results were: 68 (79%) complete/very good partial responses (CR/VGPR); 14 (16%) partial responses (PR); three (3%) less than PR; one (1 %) death from infection; and one patient not assessable for response. Five cycles yielded a CRNGPR rate of 83%, compared with a 77% rate from seven cycles. Side effects were myelosuppression, mucositis, and hearing deficits; neurotoxicity was insignificant with the lower vincristine dosage. Four patients (each received seven cycles) developed myelodysplasia/leukemia. Conclusion Five cycles of this induction regimen, plus surgery, suffice to achieve CRNGPR in approximate to80% of children with high-risk NB.