Take breast cancer as an example. There will only be pain at first, and then there will be hyperplasia and lump. If people pay attention to it at this time, further treatment can be cured, because the mass at this time is not cancer, but tumor or benign hyperplasia at most. But this kind of hyperplasia and benign tumor may develop into cancer if it is stimulated by the outside world. Take rectal cancer and intestinal cancer as examples. At first, this place with long cancer is no different from the normal intestine. However, due to hard objects scratching the intestine and growing polyps, it eventually evolves into cancer under constant stimulation, and some patients with rectal cancer often have constipation or diarrhea. Of course, what I said is not absolute, just an example.
Take myself for example. When I was young, my family was in a bad condition. When I was 4 years old, I got pneumonia. Since then, the root of the disease has fallen into my lungs and throat. Whenever I catch a cold, I will inevitably cough, and even my trachea is uncomfortable. At that time, I was also afraid of reinfection or speech in my lungs, so I usually went for routine film examination. The first time I went for a check-up, the doctor asked me if I had pneumonia. The doctor said that some old calcifications could be seen on the film, and then I told the story of pneumonia when I was a child. I casually asked the doctor if these calcifications would become tumors or cancers. The doctor said this: "Calcification points will not become cancer, cysts or benign tumors and nodules may become cancer, but they are only small nodules at first, and some are not even as big as matchsticks. If this nodule continues to develop, there is a high probability of cancer, but it does not necessarily mean cancer.
These two kinds of cancers, plus a kind of gastric cancer, have almost no symptoms in the early stage of cancer, and the cancer cells have not spread and proliferated, which does not threaten the body function. It's really hard to find unless they do a full set of tests. In the middle and late stage of cancer, people's body functions will become cancerous, such as emaciation and bloody stool. According to the location of cancer, the signals given by human body are different. Take my cousin's eldest sister-in-law for example. She has rectal cancer. At first, she didn't have any symptoms, but she often had a bad stomach. Then when she went out to travel, she had an examination and confirmed that it was rectal cancer. That was in the early days, and the doctor said that as long as the operation did not recur, there would be no major problems in the future. So my eldest sister-in-law had an operation. If she hadn't found it in advance, the doctor said that after the cancer cells spread, the human body would have serious feedback, and there would be no cure.
Moreover, the initial symptoms of many cancers are similar to headaches, colds and joint pains, and individuals simply cannot recognize them. If you want to prevent cancer, the safest way is regular physical examination. Only in this way can you prevent cancer, find it early and treat it early.