[Malignant tumors in childhood]

With the consistent use of effective multimodal treatment, including combination chemotherapy, surgery and radiotherapy, the prognosis for all types of childhood cancer has dramatically improved over the last 25 years and the current 5-year survival rate is about 60-98%. Concurrently, developments in the laboratory have improved our understanding of the biology of childhood malignancies. The availability of new imaging techniques, particularly advances in magnetic resonance imaging, have enabled more accurate assessments of tumor extent and staging. Such imaging techniques are now routinely used in radiotherapy planning to maximize treatment to tumor sites, while minimizing the exposure of normal tissues. Progress in surgery has allowed for better reconstructive techniques to repair defects created by tumor resections. The availability of blood component transfusions and hematopoietic cytokines, and advances in supportive care such as isolation techniques and preventive high-dose antibiotic therapy for infections, have allowed for the administration of increasingly intensive chemotherapies. Advances in our understanding of hematopoietic stem cells have enabled for significant extension of the techniques of bone marrow transplantation. Many of the advances in diagnosis, treatment, and our understanding of the biology of childhood cancers have emerged from studies conducted at centers with the required expertise, where multidisciplinary teams are available to coordinate the diagnosis, treatment, supportive care, and follow-up of children with cancer. The increasing population of children who survive into adulthood has renewed concern for the long-term consequences of therapy. Current studies focus on "risk-adapted" therapy, where the most intensive treatment is reserved for patients at highest risk of treatment failure, whereas treatment of children with a more favorable prognosis is designed to minimize the acute and late toxicities of therapy.