The purpose of this study is to see if more intense chemotherapy used with less radiation therapy can bring about a remission in patients with relapsed acute lymphoblastic leukemia (ALL).

In addition, we would like to use information collected on this study to answer some research questions that might benefit future subjects. The research aims are as follows: 

1) To see if tiny amounts of leukemia cells might be present in the bone marrow at the time of relapse. We want to know if the amount of these cells can tell us how well a subject might respond to treatment.
2) To look for changes in the genetic structure (DNA) of relapsed subjects. We want to see if genetic changes make a difference in how the subject responds to treatment and in the types of side effects the subject has while being treated.
3) To look at the effects that the disease and treatment have on thinking, learning, and behavior. We want to know whether or not subjects have fewer learning and other psychological problems if less CNS radiation therapy is given.