Treatment of Newly Diagnosed Acute Lymphoblastic Leukemia in Children and Adolescents

Acute lymphoblastic leukemia (ALL) is the most common cancer diagnosed in children. The cancer comes from a cell in the blood called a lymphocyte. Normal lymphocytes are produced in the bone marrow (along with other blood cells) and help fight infections. In ALL, the cancerous lymphocytes are called lymphoblasts. They do not help fight infection and crowd out the normal blood cells in the bone marrow so that the body cannot make enough normal blood cells. ALL is always fatal if it is not treated. With current treatments, most children and adolescents with this disease will be cured. The standard treatment for ALL involves about 2 years of chemotherapy. The drugs that are used, and the doses of the drugs, are similar but not identical for all children and adolescents with ALL. Some children and adolescents receive stronger treatment, especially during the first several months. A number of factors are used to decide how strong the treatment should be to give the best chance for cure. These factors are called "risk factors". This trial is studying the use of a new, updated set of risk factors to decide how strong the treatment will be. The study also will test a new way of dosing a chemotherapy drug called pegaspargase (which is part of the standard treatment for ALL) based on checking levels of the drug in the blood and adjusting the dose based on the levels.