According to a recent article published early in the online version of the journal Blood, pediatric patients with ALL should be treated according to their risk of developing a cancer recurrence following treatment. For those considered to be at a high risk of developing a recurrence, early intervention with intensified treatment provides high rates of long-term, cancer-free survival.
Acute lymphocytic leukemia (ALL), also called acute lymphoblastic leukemia, is a cancer of the bone marrow and lymph system. The bone marrow produces early blood-forming cells, called stem cells, which grow and mature into the three blood cell types: white blood cells, which fight infection; red blood cells, which carry oxygen to tissue; and platelets, which help blood to clot. ALL is characterized by uncontrolled production of immature lymphocytes (white blood cells), of which there are two types: B and T cells. These immature lymphocytes never mature enough to perform their specific function of fighting infection. In addition, these rapidly dividing cells crowd out and suppress the formation of other important blood cells, such as red blood cells, platelets and other white blood cells.
Some patients with ALL are considered to be at a higher risk of developing a cancer recurrence and ultimately have a poorer long-term outcome than other patients. Some variables that determine whether a patient is at a higher or lower risk of a recurrence are the presence of the genes MLL-AF4 or BCR-ABL, as well as the presence of even minute amounts of leukemia cells 6 weeks following initial treatment. One area that is relatively common for a cancer recurrence is the central nervous system (CNS), which includes the spinal cord and brain. Patients are often not curable once they experience a CNS recurrence and researchers have been evaluating ways to prevent these recurrences with radiation to the head or chemotherapy that can penetrate the CNS.
Researchers from St. Jude Children’s Hospital recently conducted a clinical study to evaluate outcomes in pediatric patients with ALL who were treated according to their risk of developing a recurrence. This study included 247 patients, 130 of whom were considered to be at a high risk of a cancer recurrence and were treated with intensive combination chemotherapy following initial treatment, including intensive chemotherapy to the CNS to prevent a CNS recurrence. Patients at a low risk of developing a cancer recurrence were treated with standard therapy. At approximately 5 years, progression-free survival was over 80%, and at 8 years progression-free survival was approximately 78% for high-risk patients. Recurrences specifically to the CNS occurred in only 1.7% of patients and overall recurrences occurred in only 3% of patients at 5 years of follow-up.
The researchers concluded that pediatric patients with ALL should be treated according to their risk of developing a cancer recurrence. Patients considered to be at a high risk of developing a cancer recurrence can achieve high rates of long-term, cancer-free survival with early intensive combination chemotherapy, as well as intensive chemotherapy delivered specifically to the CNS. Parents with children who have been diagnosed with ALL may wish to speak with their physician about their child’s individual risk of developing a cancer recurrence as well as the risks and benefits of intensive treatment if they are considered to be at a high risk.
Reference: Pui C-H, Sandlund J, Pei D, et al. Improved outcome for children with acute lymphoblastic leukemia: results of Total Therapy Study XIIIB at St. Jude Children’s Research Hospital. Blood. 2004; Pre-published on-line. Available at: DOI 10.1182/blood-2004-04-1616.