Each year approximately 150 out of every 1 million children younger than age 20 years are diagnosed with cancer. For children between the ages of 1 and 20 years, cancer is the fourth leading cause of death, behind unintentional injuries, homicides, and suicides. However, combined-modality therapy, including surgery, chemotherapy, and radiation therapy, has improved survival dramatically, such that the overall 5-year survival rate of pediatric malignancies is now greater than 75%. It is estimated that by the year 2020, 1 in 600 adults will be a survivor of childhood cancer.
Because pediatric malignancies are rare, cooperative clinical trials have become the mainstay of treatment planning and therapeutic advances. The Children's Oncology Group (COG), representing the amalgamation of four prior pediatric cooperative groups (Children's Cancer Group, Pediatric Oncology Group, Intergroup Rhabdomyosarcoma Study Group, and the National Wilms Tumor Study Group), offers current therapeutic protocols and strives to answer important treatment questions. A child or adolescent newly diagnosed with cancer should be enrolled in a cooperative clinical trial whenever possible. Because many protocols are associated with significant toxicities, morbidity, and potential mortality, treatment of children with cancer should be supervised by a pediatric oncologist familiar with the hazards of treatment, preferably at a multidisciplinary pediatric cancer center.
Advances in molecular genetics, cell biology, and tumor immunology have contributed and are crucial to the continued understanding of pediatric malignancies and their treatment. Continued research into the biology of tumors will lead to the identification of targeted therapy for specific tumor types with, it is hoped, fewer systemic effects.
Research in supportive care areas, such as prevention and management of infection, pain, and emesis, has improved the survival and quality of life for children undergoing cancer treatment. Long-term studies of childhood cancer survivors are yielding information that provides a rationale for modifying future treatment regimens to decrease morbidity. A guide for caring for childhood cancer survivors is now available to medical providers as well as families and details suggested examinations and late effects by type of chemotherapy received.
MAJOR PEDIATRIC NEOPLASTIC DISEASES
ACUTE LYMPHOBLASTIC LEUKEMIA
Acute lymphoblastic leukemia (ALL) is the most common malignancy of childhood, accounting for about 25% of all cancer diagnoses in patients younger than age 15 years. The worldwide incidence of ALL is about 1:25,000 children per year, including 3000 children per year in the United States. The peak age at onset is 4 years; 85% of patients are diagnosed between ages 2 and 10 years. Children with Down syndrome have a 14-fold increase in the overall rate of leukemia.
ALL results from uncontrolled proliferation of immature lymphocytes. Its cause is unknown, and genetic factors may play a ...