- Patients in groups A and B with CNS disease at presentation undergo radiotherapy to focal infiltration at entry or concurrently with total body irradiation, or whole brain radiotherapy during maintenance (if no prior CNS irradiation). At any time during the study, patients who develop marrow relapse (more than 5% leukemic blasts in bone marrow on 2 occasions), CNS relapse (blasts in CSF, cranial nerve palsy, or CNS mass), or testis or other extramedullary relapse are taken off study.