The distinctive biology of cancer in adolescents and young adults

Key Points The relative lack of progress in treating cancer in adolescents and young adults (AYAs) is in part due to a lack of appreciation of differences in the biology of malignant diseases in this age group relative to younger and older persons. Molecular, epidemiological and therapeutic outcome comparisons offer clues to this distinctiveness in most of the common cancers of AYAs, including leukaemias, lymphomas, sarcomas, melanoma, and carcinomas of the breast, colon, rectum and nasopharynx. Translational and clinical research should not assume that the biology of cancers and AYA hosts is the same as in other age groups, even if the diseases seem the same clinically and histopathologically. A systematic review of previously reported biological and therapeutic outcomes, that combines older adolescent and young adult patients with younger and older persons, should be made of biological differences if the numbers of subjects or samples permit an adequate assessment. In addition, prospective studies evaluating potential biological differences should be incorporated into investigations that include patients across the age spectrum. Therapeutic strategies tailored to the AYA age group, based on the distinct biology of the cancer and the host, might improve outcomes and prognosis. One explanation for the relative lack of progress in treating cancer in adolescents and young adults is that the biology of malignant diseases in this age group is different. Do molecular, epidemiological and therapeutic outcome comparisons support this? One explanation for the relative lack of progress in treating cancer in adolescents and young adults is that the biology of malignant diseases in this age group is different than in younger and older persons, not only in the spectrum of cancers but also within individual cancer types and within the patient (host). Molecular, epidemiological and therapeutic outcome comparisons offer clues to this distinctiveness in most of the common cancers of adolescents and young adults. Translational and clinical research should not assume that the biology of cancers and patients is the same as in other age groups, and treatment strategies should be tailored to the differences.