Pediatric Autologous Stem Cell Transplantation: A Comparison between Peripheral Blood Stem Cell and Bone Marrow

Ultra-high dose myeloablative therapy followed by autologous bone marrow transplantation has become an attractive therapeutic option for some pediatric cancer patients who do not achieve cure with conventional therapies. The source of these hemopoietic stem cells is either the bone marrow (BM) or the peripheral blood stem cells (PBSC). In this article, we review the various aspects of pediatric autologous stem cell transplantation and compare transplantation of stem cell collected from BM with that harvested from PBSC. Since most studies comparing PBSC and autologous bone marrow transplantation (ABMT) have found an engraftment advantage for PBSC, we also wanted to analyze if this translated into improved overall survival and disease free outcome. We analyzed the medical records of patients who underwent autologous bone marrow transplantation from March 1992 to July 2001 at Columbus Children's Hospital. They ranged from ages 1 year to 27 years (Median 5 years). The median survival time for 30 patients who underwent PBSC's transplant was 39.5 months, while for the 27 patients with ABMT transplant was 47.6 months. These transplantations were for a variety of disorders: neuroblastoma (n = 17), soft tissue sarcoma (n = 8). Ewing's sarcoma (n = 5), acute myelogenous leukemia (n = 4), non-Hodgkin's lymphoma (n = 3), Hodgkin's lymphoma (n = 2), Wilms tumor (n = 2), retinoblastoma (n = 2), desmoplastic small round cell tumor (n = 1), germ cell tumor (n = 1), and 12 cases of brain tumor, medulloblastoma (n = 7), ependymoma (n = 2), astrocytoma (n = 1), anaplastic glioma (n = 1), and glioblastoma multiforme (n = 1). Patients were conditioned with a variety of preparative regimens. These regimens combined either one or more chemotherapy agents with total body irradiation (TBI), or cytotoxic drugs without TBI. All patients engrafted normally with an absolute neutrophil count (ANC) exceeding 500 × 10⁶/L for three consecutive days. 12 of 30 patients who underwent PBSC transplant died compared to 12 of 27 who underwent ABMT. In both groups, relapse or progressive disease was the most common cause of death; ten cases each of PBSC and ABMT died from relapse or progressive disease. The other causes of death included: sepsis, multi-organ failure, cardiac toxicity, and post-treatment lymphoproliferative disorder. The median survival time until relapse or death for the PBSCs was 39.5 months compared to 47.6 months for ABMT. A log rank test comparing these two groups showed no statistical significance (log rank 0.013, P = 0.9). Our study, looking at the long-term advantage of PBSC over ABMT, failed to show any benefit. There was no difference in the overall or progression free survival between the two groups.