For several reasons, death from cancer in the adolescent and young adult (AYA) population of 15 to 39 years of age is imbued with greater significance than cancer death in children or older adults. Historically, AYAs once had the best survival rates from cancer in general, and thus, deaths in this group were the least expected. With the dramatic improvement in the cure and long-term survival of children in the Western world with cancer, AYAs with cancer lost their advantage in survival rates by year 2000.1 With the mean lifespan in the United States currently 79 years,2 AYAs can expect to live a mean of 40 to 65 years depending on the age at diagnosis of cancer, if their cancer or its sequelae does not kill them. When the relative incidence of invasive cancer in the United States is considered—AYAs are 7.4 times more likely (in 2012, the incidence per 100 000 was 71.2 in AYAs vs 15.7 in patients younger than 15 years1) to receive a diagnosis of invasive cancer than children and young adolescents younger than 15 years—the impact of fatal cancer on years of life lost in AYAs is several times greater. In patient-years of life affected, cancer in AYAs ranks fourth when compared with all individual cancers (after breast, prostate, and lung cancer in that order) and affects 4 times as many years of life as in children and young adolescents, despite only 6% of all invasive cancer being diagnosed in AYAs (calculated from Surveillance, Epidemiology, and End Results data2). These differences between AYAs and either younger or older patients with cancer are even greater if noninvasive cancer is included because AYAs are the age group with the greatest proportion of noninvasive cancer, in situ, benign, and borderline tumors of the cervix, breast, ovary, and central nervous system (R. D. Barr, MB ChB, MD; L. R. Ries, PhD; D. R. Lewis, PhD; L. C. Harlan, PhD; H. M. Keegan, PhD; B. H. Pollock, MPH, PhD; A. Bleyer, MD; US National Cancer Institute Science of AYA Oncology Epidemiology Working Group; unpublished data; March 2015).