OUTLINE: Patients are stratified by disease characteristics (disseminated lymphoblastic lymphoma vs localized lymphoblastic lymphoma [localized lymphoblastic lymphoma is closed to accrual as of 10/2005]) and age. Patients with CNS negative disseminated lymphoblastic lymphoma are randomized to 1 of 4 treatment arms*. Patients with testicular involvement at diagnosis are nonrandomly assigned to arm IV and do not receive testicular radiotherapy. Patients with localized lymphoblastic lymphoma (closed to accrual as of 10/2005) are not randomized.