Malignant diseases in childhood and adolescence
Cancer is rare in children and adolescents. The probability for a newborn child to develop cancer within the first 18 years of life is 0.3 %. Nevertheless, cancer is the most fatal among childhood diseases and, following accidents, the second most common cause of death in children and adolescents. According to statistical data provided by the German Childhood Cancer Registry, about 2,200 young patients under 18 years of age are newly affected each year. This corresponds to a yearly incidence of 170 new diagnoses per million children in this age group.
Children are not "little adults". Therefore, cancer in the young differs from cancer in adults in many ways. This does not only refer to the type of disease and its incidence, but also the treatment approaches and probability of cure. Hence, carcinomas (tumours of the epithelial tissue) for example, account for 1.5 % and thus are very rare in childhood and adolescence, while in adults, they represent more than 90 % of newly diagnosed malignancies. On the other hand, more than a quarter of children and adolescents with cancer are diagnosed with embryonal tumours; these are tumours arising from extremely immature (undifferentiated) cells and subsequently grow rapidly.
The most frequent malignant diseases in children and adolescents are leukaemias (30 %), followed by tumours of the central nervous system (24 %) and lymphomas, which account for about 14 %. Soft tissue sarcoma (5.7 %), neuroblastoma (5.5 %) and nephroblastoma (Wilms tumour, 4.2 %) are also considered relatively frequent. In general, children and adolescents can be treated more successfully than adults.
The following table of diseases in childhood and adolescence shows which cancer groups relate to which diagnoses and clinical trials.