The majority of children with acute myeloid leukemia (AML) or acute lymphoid leukemia (ALL) achieve a complete disappearance of cancer following initial treatment with chemotherapy. However, many of these patients will experience a return of the cancer, resulting in a survival rate of less than 50%. Results from a recent study published in the Journal of Clinical Oncology showed a high survival rate in infants with AML or ALL who were treated with a stem cell transplant following high-dose treatment.
Acute myeloid leukemia and acute lymphoid leukemia are both considered cancers of white blood (immune) cells. The bone marrow produces early blood-forming cells, called stem cells, which grow and mature into 3 different types of blood cells: red blood cells to supply Oxygen to tissues, platelets to aid the blood in clotting and white blood cells which fight infection. Acute myeloid leukemia and acute lymphoid leukemia are characterized by the uncontrolled growth of immature types of white blood cells in the bone marrow, resulting in excess accumulation of these cells. These leukemia cells crowd the bone marrow, suppressing formation and function of other blood cells, and ultimately invade other parts of the body including the blood, lymph system, and vital organs. Acute leukemias are rapid growing cancers and treatment must be aggressive for an optimal chance of cure.
High-dose chemotherapy and/or high-dose radiation therapy are aggressive treatments that are highly effective at killing cancer cells. Unfortunately, these treatments do not distinguish between cancer cells and healthy cells, often destroying bone marrow stem cells, which can lead to life threatening complications such as anemia, bleeding and infection. The treatment strategy utilizing stem cell transplantation (SCT) is an attempt to restore the blood forming stem cells after high-dose treatment has reduced them to dangerously low levels. Stem cells can either be collected from the patient prior to high-dose therapy, frozen, and re-infused into the patient following therapy (autologous SCT) or healthy stem cells can be collected from a donor and infused into the patient following therapy (allogeneic SCT).
In a recent study, researchers from Spain evaluated survival rates of 26 infants with either AML or ALL. All of these patients received a stem cell transplant, either autologous or allogeneic, after receiving high-dose chemotherapy or high-dose radiation. Twenty-two patients were in their first remission (disappearance of cancer following treatment), 3 were in their second remission, and 1 was experiencing a cancer recurrence. Over 60% of these patients were alive and free of cancer 5 years following the transplantation. Importantly, over 70% of these patients who were in first remission were alive and free of cancer 5 years following transplantation. Survival rates were highest in patients who received treatment within 4 months of their first remission. There was no difference in survival between infants receiving autologous or allogeneic stem cell transplants, nor was there a difference in survival between patients receiving initial treatment with high-dose chemotherapy or high-dose radiation. Long-term survivors from this study did not suffer from significant long-term side effects and are doing intellectually and physically well.
Results from this study are important, indicating the effectiveness of high-dose treatment followed by stem cell transplantation for infants with AML or ALL. Early initiation of treatment increases chances for survival. Importantly, total body irradiation may be substituted with chemotherapy, achieving comparable outcomes regarding survival rates while sparing patients from potential long-term side effects associated with radiation therapy. Parents that have children with AML or ALL may with to speak with their physician about the risks and benefits of high-dose chemotherapy and stem cell transplantation or about the participation in a clinical trial utilizing other promising new treatment strategies. Two sources of information on ongoing trials that can be discussed with a doctor include comprehensive, easy to use services provided by the National Cancer Institute (cancer.gov) and eCancerTrials.com. eCancerTrials.com also performs personalized clinical trial searches on behalf of their patients. (Journal of Clinical Oncology, Vol 18, No18, pp 3256-3261, 2000)