Chemotherapy and Autologous Stem Cell Transplant Improve Outcome for Children
Children and adolescents with high-risk neuroblastoma have better outcomes after treatment with high-dose chemotherapy and autologous stem-cell transplant than after oral maintenance chemotherapy, according to the results of a clinical trial published in the journal Lancet Oncology.
Neuroblastoma is a disease in which cancerous cells form in the nerve tissues of the adrenal gland, neck, chest, or spinal cord. Although neuroblastoma is rare, affecting roughly 650 children and adolescents in the United States each year, it is the most common malignancy diagnosed in infants. The severity of neuroblastoma is classified as “high”, “intermediate”, or “low” based on the stage of the tumor, certain other characteristics of the tumor, and the age of the child. High-risk neuroblastoma is more difficult to cure than low- or intermediate-risk neuroblastoma.
Typically, patients diagnosed with neuroblastoma initially undergo surgery plus standard chemotherapy with or without radiation therapy. Following this initial treatment, patients generally receive further therapy to kill any cancer cells that may remain in the body. Maintenance therapy refers to standard doses of chemotherapy given following initial therapy; patients with high-risk neuroblastoma may undergo high-dose therapy with a stem-cell transplant following initial therapy as a more aggressive treatment approach for their disease.
While high-dose chemotherapy followed by a stem-cell transplant may be an effective approach for children with high-risk neuroblastoma, there is little information available about the outcome of this treatment. The rationale for using high-dose chemotherapy is that it kills more cancer cells than moderate doses. However, high-dose chemotherapy also results in more side effects, particularly to the blood-producing hematopoietic stem cells. Hematopoietic stem cells are immature blood cells produced in the bone marrow that mature into red blood cells (which carry oxygen to tissues), white blood cells (which fight infection), and platelets (which aid in blood clotting). An autologous stem cell transplant involves the collection of a patient’s own stem cells prior to treatment and re-infusion of the “harvested” stem cells after high-dose chemotherapy to restore depleted blood cell levels.
To compare survival after high-dose chemotherapy and autologous stem cell transplant to survival after oral maintenance chemotherapy (standard doses of chemotherapy), researchers conducted a randomized clinical trial among 295 children and adolescents in Germany and Switzerland with high-risk neuroblastoma. After initial chemotherapy and surgery, half of the children received high-dose chemotherapy (melphalan, etoposide, and carboplatin) and autologous stem-cell transplant, and half of the children received oral maintenance chemotherapy (cyclophosphamide). At the end of three years of follow-up, patients who had received high-dose chemotherapy and autologous stem-cell transplant were more likely to survive without progression or recurrence of their neuroblastoma than patients who had received oral maintenance chemotherapy. There was no significant difference, however, in overall three-year survival. Two patients died from treatment effects during the initial round of chemotherapy, no patients died as a result of oral maintenance chemotherapy, and five patients died as a result of high-dose chemotherapy and stem-cell transplant.
The researchers conclude that in spite of the higher risk of treatment-related death following high-dose chemotherapy and autologous-stem cell transplant, patients with high-risk neuroblastoma who received this treatment survived longer without a worsening of their disease than patients who received oral maintenance chemotherapy. Parents of children who have neuroblastoma may wish to speak with their physician about the participation in a clinical trial further evaluating treatment strategies for this disease. Sources of information regarding ongoing clinical trials include the National Cancer Institute (www.cancer.gov).
Reference: Myeloablative megatherapy with autologous stem-cell rescue versus oral maintenance chemotherapy as consolidation treatment in patients with high-risk neuroblastoma: a randomized controlled trial. Lancet Oncology. Early online publication August 11, 2005.