Patterns of cancer treatment in different age groups in Japan: an analysis of hospital-based cancer registry data, 2012-2015

Background: Because of the physiological decline and the diversity of preferences, treating older patients with cancer is challenging. Given the insufficient evidence applicable to treating cancer in older patients, some clinical guidance is necessary. This study provides a description of current treatment practices in Japan, which may shed light on possible treatment options. Methods: Using data from the national database of hospital-based cancer registries, we described the first-course treatment of nine common cancers in patients who received care in Designated Cancer Care Hospitals between 2012 and 2015. We compared the patterns of first-course cancer treatment between younger and older patients. Results: In total, 1 383 066 cases were analysed. The proportion of patients aged >75 years receiving first-course treatment has gradually increased since 2012 (range: 0.9% point increase for colorectal cancer to 2.7% point increase for stomach cancer). A higher proportion of patients aged >= 85 years, compared with younger patients, did not receive any treatment. Conclusions: Based on this cancer registry-based analysis, older patients-in particular those >= 85 years old at diagnosis and with advanced stage cancer-are less likely to receive anti-cancer treatment than younger patents are. Further research is warranted to identify patient characteristics that predict which older patients are most likely to benefit from active treatment.