Childhood, adolescent and young adult cancer incidence in Japan in 2009–2011

Little is known about cancer incidence among children and youths in Japan. We aimed to describe cancer incidence in Japan focusing on childhood, adolescence and young adulthood (AYA). Cancer incidence data were obtained from the Monitoring of Cancer Incidence in Japan project. For the 2009–2011 incidence, the data were collected from 40 prefectures, of which data from 27 prefectures meeting quality standards were analyzed (population coverage: 38.6%). Cancers diagnosed in 0–39 years of age were classified according to the International Classification of Childhood Cancer (version 3). Crude incidence rates of cancer (including benign or behavior-unknown brain tumors) were 122.7, 142.2, 310.7, and 910.6 for the 0–14, 15–19, 20–29, and 30–39 age groups, respectively (per million population). Using the sex- and age-specific incidence rates, the national estimates of cancer incidence were 2055 for 0–14 years (1118 males and 937 females), 864 for 15–19 years (450 males and 414 females), 4246 for 20–29 years (1699 males and 2547 females), and 16 295 for 30–39 years of age (5101 males and 11 194 females). The five leading cancers were leukemia, cancer of the central nervous system (CNS), lymphoma, malignant germ cell and other gonadal tumors, and neuroblastoma in childhood cases (0–14 years old); leukemia, malignant germ cell and other gonadal tumors, lymphoma, CNS, and malignant bone tumors in adolescence (15–19 years old). The leading cancer in 20–29 years of age was malignant germ cell other gonadal tumors (mainly testis and ovary), whereas female breast cancer was most frequent in 30–39 years of age. These results provide an overall picture of childhood and AYA cancer in Japan.