Chapter 17: Acute Lymphoblastic Leukaemia

Acute Lymphoblastic Leukaemia exploration of haematology focuses on a critical malignancy characterized by the rapid expansion of immature lymphoblasts within the marrow, identifying it as the most prevalent cancer affecting the pediatric population. While predominantly a childhood illness with a peak incidence in early youth, the disease exhibits a secondary rise in frequency among older adults, with the majority of cases originating from the B-cell lineage. The discussion delves into the complex pathogenesis of the condition, highlighting how initial genetic mutations often occur before birth, followed by a secondary transforming event post-birth that may be triggered by environmental factors or specific immune responses to common infections. Clinically, patients present with symptoms stemming from systemic marrow failure, such as significant anemia, frequent infections due to low white cell counts, and abnormal bruising, alongside signs of tissue infiltration like swollen lymph nodes, enlarged organs, or mediastinal masses. Diagnosis relies on a multi-faceted approach involving morphological assessment, immunophenotyping to distinguish between B-cell and T-cell origins, and advanced cytogenetic analysis to identify prognostic markers like hyperdiploidy or the Philadelphia chromosome. Modern classification systems categorize these leukaemias based on specific molecular abnormalities, which are essential for determining the most effective clinical protocols. Therapeutic strategies are typically structured into several intensive phases: achieving initial remission, consolidating gains through high-dose regimens, protecting the central nervous system from infiltration, and long-term maintenance to prevent relapse. A pivotal advancement in contemporary management is the monitoring of minimal residual disease, where highly sensitive tests detect microscopic traces of cancer cells to guide treatment intensity and risk adjustment. For high-risk or resistant cases, the chapter reviews cutting-edge interventions including tyrosine kinase inhibitors, bispecific antibodies that recruit the body’s own immune cells, and chimeric antigen receptor T-cell therapy. Despite the challenges, survival rates for younger patients have improved dramatically, though the prognosis remains more guarded for adults due to differing genetic profiles and treatment tolerances.