Purpose: Patients with high-risk neuroblastoma who have multiple copies of MYCN fare much worse than do those without MYCN amplification; however, it has not been clarified whether intensified chemotherapy with or without blood stem cell transplantation can alter the extremely poor prognosis of patients with amplified MYCN.
Methods and results: Between 1985 and 1999, 301 patients older than age 12 months with stage 4 neuroblastoma were treated. From January 1985 to February 1991, 80 patients with stage 4 neuroblastoma with and without MYCN amplification uniformly received induction chemotherapy with regimen A(1) (cyclophosphamide 1,200 mg/m(2) and vincristine 1.5 mg/m(2) on day 1, tetra-hydropyranyl [THP]-Adriamycin 40 mg/m(2) on day 3, and cisplatin 90 mg/m(2) on day 5). Among 22 patients with MYCN amplification, nine (40.9%) achieved a complete remission and seven (31.8%) underwent stem cell transplantation. Of 58 patients without MYCN amplification, 43 (74.1%) achieved a complete remission and 14 (24.1%) underwent stem cell transplantation. The 5-year relapse-free survival rates were 23.2% for stage 4 patients with MYCN amplification and 33.3% for those without MYCN amplification (P = 0.029); the 5-year overall survival rates were 32.8% for stage 4 patients with MYCN amplification and 42.8% for those without MYCN amplification (P > 0.05). From March 1991 to June 1998, patients with stage 4 neuroblastoma who had 10 or more copies of MYCN were treated with regimen A(3) (cyclophosphamide 1,200 mg/m(2) per day on days 1 and 2, THP-Adriamycin 40 mg/m(2) on day 3, etoposide 100 mg/m(2) per day on days 1 to 5, and cisplatin 25 mg/m(2) per day on days 1 to 5); those with fewer than 10 copies of MYCN received regimen new A (cyclophosphamide 1,200 mg/m on day 1, THP-Adriamycin 40 mg/m on day 3, etoposide 100 mg/m per day on days 1 to 5, and cisplatin 90 mg/m on day 5), which is similar in intensity to regimen A. Among 88 patients with MYCN amplification, 63 (71.6%) achieved a complete remission and 63 (71.68%) underwent stem cell transplantation. Of 133 patients without MYCN amplification, 93 (69.9%) achieved a complete remission and 71 (53.4%) underwent stem cell transplantation. The 5-year relapse-free survival rates were 36.0% for stage 4 patients with MYCN amplification and 32.2% for those without MYCN amplification (P > 0.05), the 5-year overall survival rates were 34.0% for stage 4 patients with MYCN amplification and 38.9% for those without MYCN amplification (P > 0.05). The difference in relapse-free survival rates was significantly different (P = 0.003) between patients with MYCN-amplified tumor treated before (regimen A(1)) versus after 1991 (regimen A(3)).
Conclusions: With the use of the more intensive induction regimen A plus blood stem cell transplantation for MYCN-amplified patients, survival curves for those with or without MYCN amplification now appear similar. Higher doses of chemotherapy may ameliorate the effect of MYCN amplification in patients with high-risk neuroblastoma.