Classification and risk stratification in T-lineage acute lymphoblastic leukemia

Cure rates for patients with acute lymphoblastic leukemia (ALL) have improved markedly in recent decades, in part due to risk stratification incorporating leukemia genomics, response to treatment, and clinical features to be able to determine at diagnosis which patients are more likely to relapse or have refractory disease. While risk stratification is well-developed for patients with B lineage ALL (B-ALL), it remains challenging for those with T lineage ALL (T-ALL). Prognostic factors validated across clinical trials and real-world data in T-ALL include age, central nervous system (CNS) involvement, and minimal residual disease (MRD) response. Immunophenotype, including early T-cell precursor (ETP) ALL is widely used to classify T-ALL, but is not consistently associated with outcome in multivariable risk models. Historically, few genetic alterations have been consistently associated with outcome, but recent comprehensive, large-scale genomic profiling has identified multiple genetic subtypes and alterations associated with outcome independent of MRD. This review highlights ongoing efforts to identify reliable prognostic biomarkers and underscores the potential of genomics-based classification to guide future T-ALL treatment strategies.