Stratification and Treatment Considerations in B-Cell Precursor and T-Cell Acute Lymphoblastic Leukemia

Outcomes for pediatric acute lymphoblastic leukemia (ALL) have improved dramatically since the 1980s, now with approximately 90% survival at 5 years. Improved outcomes and reduced toxicity are related to widespread adoption of standardized research protocols, improved prevention and treatment of central nervous system (CNS) leukemia, and risk-based stratification of treatment. This chapter will discuss risk stratification and treatment strategies for B-cell (B-ALL) and T-cell (T-ALL) ALL, as well as undifferentiated and mixed phenotype (MPAL) acute leukemias. Other chapters address Philadelphia chromosome positive (Ph+), ABL-class fusion, and infant leukemias. Previously, risk categorization was based solely on clinical criteria such as age, white blood cell count, and chemotherapy response; however, the discovery of recurring genetic abnormalities has helped narrow individual prognosis and guide care. Multi-agent conventional chemotherapy, with allogeneic stem cell transplantation for suitable individuals, remains the backbone of therapy. However, immunotherapies such as inotuzumab, blinatumomab, and chimeric antigen receptor (CAR) T cells are now being tested in frontline protocols in an effort to increase survival and decrease toxicity.