How is cancer detected? Can a general physical examination detect cancer?

Some can be detected by general physical examination, such as thyroid cancer, which can be detected by palpation, breast cancer and cervical cancer can also be detected by general physical examination, liver cancer and ovarian cancer can be detected by B-ultrasound, but some cancers can not be detected, so we need to focus on adding some inspection items to some parts during our annual physical examination. In fact, many cancers can be seen through filming, but some people just want to take a blood sample for a physical examination, which is absolutely impossible to find out. We have to take pictures and do B-ultrasound. If any abnormality is found, the individual parts must be checked again. Don't think that the doctor asked you to check again just to cheat you, so the doctor is also helping you eliminate hidden dangers. Many people have cancer, which is usually found in the late stage, not because they don't pay attention to their health. Some of them have regular physical examinations every year, but they don't find out that they have cancer. Therefore, routine examination is not necessarily suitable for them, but only for most people. What if they have physical problems? I just went for a general checkup. If it's okay, I think it's wrong if it's okay. I need to check a single part. Every year's physical examination should have its own key examination items. For example, if you often have a stomachache, you need to add a stomach examination to our physical examination items. If you smoke a lot, you must take a chest X-ray to see if there are any nodules in your lungs. It's still a small tumor. Girls have to do breast screening and cervical cancer screening every year, and finally do a B-ultrasound to see if there are uterine fibroids in their uterus. Boys must also have a B-ultrasound to see if there is anything wrong with their prostate.