Table 1. COG B-Cell ALL Relapse Risk Stratificationa and Clinical Trials
| | Isolated CNS or Testicular Relapse [Clinical Trial] | Bone Marrow or Combined Relapse [Clinical Trial] |
| <18 months from diagnosis | Intermediate risk [COG-AALL0433]b | |
| 18–36 months from diagnosis | | |
| >36 months from diagnosis | | Intermediate risk [COG-AALL0433]b |
| ALL = acute lymphoblastic leukemia; CNS = central nervous system; COG = Children's Oncology Group. |
| aAll relapsed T-cell ALL is considered high risk—COG-AALL07P1. |
| bAll intermediate-risk patients with matched siblings choosing allogeneic transplant, and all high-risk patients undergoing related or unrelated transplantation are encouraged to enroll in COG-ASCT0431 (see below) after completion of the three induction blocks associated with these protocols. |
