Cancer, also known as malignant tumor, will often show precursor symptoms, such as progressive weight loss, progressive loss of appetite, mental fatigue, and poor sleep, and when these precursor symptoms occur, you need to go to the hospital for a physical examination. If you have any of these symptoms, you should go to the hospital for medical checkups. Tumor markers for men or tumor markers for women should be detected, and imaging screening should be done. Therefore, systematic tests must be performed to find the specific causes of these precursor symptoms, otherwise it will be difficult to treat cancer when it appears, and most tumors are already in advanced stages when they are detected.