This study is an observational research. 1. The Delphi method is used to screen the evaluation dimensions of the CGA screening tool and determine the most suitable assessment questions/items. 2. Conduct a CGA for elderly cancer patients, including the evaluation content of the dimensions above. Analyze the items selected in the first round of screening to determine the optimal items for the screening tool; develop screening tool 1.0 by assigning weights and setting thresholds for each item. 3. Investigators use the initially formed screening tool to conduct one-on-one patient testing and consult with a clinical expert panel to provide feedback on the tool's clarity, relevance, clinical applicability (localization), and feasibility, refining and improving its content and management process, leading to the revision of screening tool 2.0. 4. Validate the reliability and validity of the screening tool to ensure the stability, reliability, and effectiveness of the scale tool in practical application. 5. Evaluate patients using both the G8 and the screening tool, conducting external validation of screening tool 2.0 against G8 as a benchmark, further assessing the sensitivity, specificity, and accuracy of the screening tool. 6. Clinical validation of the screening tool. Follow up with patients involved in the assessment during the study, comparing different evaluation results with the efficacy of anti-tumor treatment and the risk of related adverse reactions, exploring the predictive ability of the CGA screening tool for anti-tumor treatment. The research data is sourced from the electronic medical record database and hospital information system of Sichuan Cancer Hospital, collecting clinical pathological characteristics from medical records, including gender, age, clinical stage at diagnosis, and information related to anti-tumor treatment.