Young adults: a unique group in cancer epidemiological research

[...]on the basis of the 10th revision of the International Classification of Diseases (ICD-10), the authors describe the cancer burden of the 27 major cancer types in adults, resulting in an over-representation of tumours common among older adults (eg, prostate cancer) and under-representation of paediatric tumours and cancers that are typical in young adults. [...]sarcomas other than Kaposi's sarcoma are not described, despite being among the ten most common cancer types in young adults.2,3 In people aged 20-39 years, the overall incidence of cancer increases exponentially as a function of age, with most tumours, including carcinomas and non-Hodgkin lymphoma, following this pattern. By contrast, paediatric cancers, such as acute lymphocytic leukaemia and (embryonal and alveolar) rhabdomyosarcoma, show decreasing incidence in young adults, whereas other tumours have a peak incidence between 20-39 years of age (eg, Hodgkin's lymphoma and germ cell testicular malignancies).4 ICD-10 categorises malignancies according to organ of origin, because adult cancers are predominantly epithelial neoplasms arising from a certain organ.