Geriatric Assessment in Oncology: Evolution, Evidence, and Implications for Geriatric Medicine in Japan

This review summarizes the evolution of recommendations for geriatric assessment (GA), the randomized evidence underpinning GA-guided management (GAM), and current implementation challenges in Japan. From the combined perspectives of oncology and geriatric medicine, we discuss how GA relates to comprehensive geriatric assessment (CGA), and argue that GA is best understood as an oncology-adapted extension of CGA. Recent trials show that active, multidisciplinary implementation of GA is associated with improvements in treatment toxicity, functional status, communication, and quality of life. In Japan, GA remains underused because of workforce limitations and structural barriers, despite its conceptual fit with the national long-term care insurance (LTCI) system. Progress will require practical workflows that link assessment to management, selective integration of GA with LTCI information to reduce duplication, and sustained collaboration between oncology and geriatrics. Overall, GA has moved beyond risk stratification toward a pragmatic, evidence-supported approach that may help reframe cancer care for older adults in Japan.