Impact of Central Nervous System (CNS) Leukemia Status-Based Therapeutic Protocol Change on the Incidence of CNS2 Diagnosis in Pediatric B-Lymphoblastic Acute Leukemia

B-lymphoblastic acute leukemia (B-ALL) is the most prevalent cancer among children, and prophylactic central nervous system (CNS) therapy has significantly contributed to high cure rates for the past 50 years. However, relapses in bone marrow and/or CNS continue to pose challenges to achieving cure for all patients, especially in those with high-risk disease. CNS status at diagnosis, defined as CNS1 (no blasts present), CNS2 (blasts with