الفهرس | Only 14 pages are availabe for public view |
Abstract Malignant solid tumors of children are histologically very diverse and a substantial proportion consists of charachteristic entities that are rarely seen in adults. Therefore, it is appropriate to group childhood cancers in a way which more fully takes morphology into account. The current scheme of childhood tumors is the international classification of childhood cancer which contain 12 main diagnostic groups: Leukemias, myeloproliferative diseases, and myelodysplastic diseases lymphomas, and reticuloendothelial neoplasms, CNS and miscellaneous intracranial, and intraspinal neoplasms, neuroblastoma, and other peripheral nervous cell tumors, retinoblastoma, renal tumors, hepatic tumors, malignant bone tumors, soft tissue and other extraosseous sarcomas, germ cell tumors, trophoblastic tumors, and neoplasms of gonads, other malignant epithelial neoplasms and malignant melanoms, other and unspecified malignant neoplasms. The annual incidence of cancer in children under 15 years of age is usually between 100 and 160 per million. There is a risk of 1 in 650 to 1 in 400 that a child will be affected during the first 15 years following birth. Despite intensive research over several decades, very little is known about the causes of most childhood cancers. Some of the most well established risk factors are genetic in nature. An increasingly long list of hereditary syndromes, mostly associated with identified single gene defects, carry a raised risk of specific childhood cancers. Population mortality rates from childhood cancer in western countries have fallen dramatically since the mid-20th century, in line with the moderate increase in incidence and very marked improvements in outcome. In wealthy industrialized countries, mortality was typically around 25-30 per million. It was considerably higher in Eastern Europe, reflecting the lower survival rates still obtained in that region. |