A single institutional pilot study was conducted in which 12 poor-risk
neuroblastoma (NB) patients were uniformly treated with multi-agent
induction chemotherapy followed by myeloablative
consolidation chemotherapy and unpurged peripheral blood stem cell (PBSC) rescue. In addition to using standard criteria for evaluating response to
induction chemotherapy,
tumor cell contamination of the peripheral blood and/or bone marrow was analyzed in seven patients by immunocytology using a panel of five anti-NB
monoclonal antibodies. Seven patients had morphologic evidence of
bone marrow disease at the time of diagnosis, and two additional patients had
tumor cells detected in bone marrow samples by immunocytology prior to the second cycle of
chemotherapy. After three cycles of
chemotherapy, two of the 12 patients continued to have evidence of
bone marrow disease. Samples from 29 PBSC harvests collected from nine patients were also analyzed for the presence of contaminating
tumor cells by immunocytology. In each case, the stem cells were found to be free of
tumor. Eleven of the 12 patients underwent myeloablative
therapy and PBSC rescue; five patients remain alive without
disease progression, 28+ to 53+ months from diagnosis, and six patients have developed recurrent disease. We conclude that PBSCs can be successfully harvested from children with NB, and used for hematopoietic reconstitution following myeloablative
chemotherapy. However, more effective
therapy for poor-risk NB patients is still urgently needed.