In urologic oncology, which often involves older patients, it is important to consider how to manage their care appropriately. Geriatric assessment (GA) is a method that can address the specific needs of older cancer patients. The GA encompasses various assessment domains, but these domains exhibit variations across the literature. Some of the common items include functional ability, nutrition, comorbidities, cognitive ability, psychosocial disorders, polypharmacy, social and financial support, falls/imbalance, and vision/hearing. Despite the diversity of domains, there is limited consensus on reliable measurement methods. This review discusses the role of GA in managing urologic cancer in unique scenarios, such as those necessitating temporary or permanent urinary catheters or stomas due to urinary diversion. A comprehensive GA is time and human-resource-intensive in real-world clinical practice. Hence, simpler tools such as the Geriatric-8 (G8), capable of identifying high-risk patients requiring a detailed GA, are also under investigation in various contexts. Therefore, we conducted a systematic literature review on the G8. Our findings indicate that patients with low G8 scores encounter difficulties with stoma self-care after urinary diversion and have higher risks of urinary tract infections and ileus after radical cystectomy. The utilization of G8 as a screening tool for urologic cancer patients may facilitate the delivery of appropriate and personalized treatment and care.