The aim of this study was to examine the status of cancer patients in the adolescent and young adult (AYA) population in Nagano Prefecture, using data from the hospital-based cancer registry (HBCR). Patients in the AYA population (15-39 years of age) included in the HBCR from January 2016 to December 2018 in Nagano Prefecture were analyzed in this study.
Results ; A total of 1640 (male : 386, female : 1254) were enrolled. The number of registered patients markedly increased over the age of 25 and 70％ of patients were observed at 30-39 years old. The distribution of cancer types in AYA was dependent on age and sex. The increased numbers were due to the increase in breast and cervical cancer in females. Most cases of cervical cancer were detected in early stages and by health screening, but the frequency of advanced staged breast cancer (stage IV) in the AYA population was similar to that in non-AYA population breast cancer and 70％ of breast cancer was detected not by health screening but mainly by symptoms in Nagano Prefecture. In addition, the frequency of spinal-brain tumor in Nagano Prefecture was relatively higher compared with that in national HBCR data in Japan.
Such information provides an overview of AYA cancer and reveals that a substantial number of AYA are diagnosed every year in Nagano Prefecture. Hospital-based cancer registries can be powerful tools for evaluating the epidemiology of cancer in Nagano Prefecture.