Coverage of the hospital-based cancer registries and the designated cancer care hospitals in Japan

Background: Hospital-based cancer registries were developed to describe and improve clinical care for cancer patients. We described the hospital-based cancer registry coverage as a reference for the users, including researchers, policymakers and clinicians. Methods: The hospital-based cancer registry coverage was defined as the proportion of new cases registered in the hospital-based cancer registry to the National Cancer Registry as the denominator. To examine the coverage of respective cancer types, age groups and prefecture in the hospital-based cancer registry, cases were grouped based on the 10th International Statistical Classification of Diseases and Related Health Problems and were compared with the published report of the National Cancer Registry in 2017. Results: The overall hospital-based cancer registries coverage was 71.7%, and 52.5% of patients were treated at designated cancer care hospitals. The hospital-based cancer registries coverage and treatment rates at designated cancer care hospitals varied per cancer type, age group, and prefecture. The hospital-based cancer registries covered over 80% of the patients with cancers of the larynx, uterus, oesophagus, lip, oral cavity, pharynx and skin, whereas patients' coverage with thyroid cancer was relatively low. The hospital-based cancer registry coverage of young patients (<15 years) was >80%, whereas that for elderly patients (>= 85 years) was <55%. The range of coverage in each prefecture was from 43.0 to 89.7%. Over 70% of the patients with cancers of the larynx, lip, oral cavity and pharynx were treated at designated cancer care hospitals. Conclusions: The hospital-based cancer registry coverage is similar to 70% of all cancers. Because the coverage differed across cancers and age groups, the respective target groups' analysis should consider this factor.