Progress in the Curative Treatment of Childhood Hematologic Malignancies

Abstract

JNCI | Editorials 1271 Hematologic malignancies account for approximately 40% of childhood cancer ( 1 ). Progress in the curative treatment of this group of cancers is one of the great medical success stories of the 20th century. There have been improvements in outcome for all major subtypes of pediatric leukemias and lymphomas, the most dramatic of which has been in acute lymphoblastic leukemia (ALL), the commonest childhood malignancy. At the time that the National Cancer Act of 1971 (Public Law 92-218) made the “conquest of cancer a national crusade” (President Richard M. Nixon, December 23, 1971) fewer than 10% of children with ALL survived for 10 years after diagnosis. Survival rates for children diagnosed with ALL have increased steadily over ensuing eras and now exceed 80% ( 2 , 3 ). Improvements in survival for childhood hematologic malignancies have been achieved as the result of serial clinical trials conducted by pediatric oncology cooperative groups and large single clinical research centers. Essential to these therapeutic advances has been the development of effective agents, along with combination chemotherapy and treatment phase – specific and central nervous system – directed regimens. The definition of clinical, pathological, and biologic risk groups has facilitated the critically important evolution of risk-based treatment stratification. This risk-based treatment approach occurred largely in the absence of new therapeutic agents over the past decade and represents the application of individualized cancer therapy before the introduction of molecularly targeted agents. Intensified regimens, including the judicious use of stem cell