[Therapeutic approaches to hematological malignancies in adolescents and young adults].

Hematological malignancies (HM) comprise the major proportion of the cancer incidence and mortality in the adolescent and young adult (AYA) age group. Even though age-related differences in tumor biology have been reported in HM, further biological studies are warranted for elucidating age-related differences in AYAs. Hemato-oncologists and pediatric oncologists frequently follow various treatment strategies for HM, as the treatment strategy that is more suitable for this age group remains unclear. Recently, the involvement of pediatric oncologists has increased because the advantage of pediatric-type treatment has been demonstrated in acute lymphoblastic leukemia (ALL) and the significance of long-term follow-up has been clarified. However, for HM, except for ALL, the pediatric- and adult-type therapy that is more suitable for AYAs remains unclear. This review aimed to describe the challenges in the context of major HM affecting the AYA age group (acute leukemia and lymphoma). For assessing the outcome of AYAs with HM, we need to consider not only the treatment strategy but also other factors such as differences in aging and tumor biology. Furthermore, it is imperative to develop a therapy that resolves psychosocial problems peculiar to AYAs.