Conclusions, Perspectives, and Future Considerations

As a result of the AYA age range adopted by the US National Cancer Institute Progress Review Group, the authors of this second edition have risen to the challenge of extending the upper age limit from 29 to 39 years. This has uncovered some unanticipated revelations, especially in the realms of epidemiology and biology. For example, in the former, a remarkable and hitherto unknown incidence of prostate cancer in young adults has come to light, while in the latter, the age-related trajectory of characteristics that typify cancers in the AYA population has been expanded to bridge the gap between adolescents and older adults, as in acute lymphoblastic leukemia (ALL) and colorectal cancers. Another important finding is the overdiagnosis of some cancers in AYAs, as best evidenced by renal and thyroid carcinomas. These data have been amplified in the chapters on individual diseases.