The theme of World Cancer Day 2015 is “Cancer prevention and control goals are not far away”, which advocates to gradually achieve early detection, diagnosis and treatment of cancer through establishing healthy lifestyles, early diagnosis and treatment, ensuring effective treatment, and maximizing patient survival treatment, so as to promote the development of cancer prevention and control. The development of cancer prevention and control. How does cancer kill people? The main reason for people to talk about cancer is its high mortality rate. But when it comes to how cancer actually kills patients, many people may not be able to say it. Why someone grows a very big tumor and is fine after the surgery, but someone’s tumor is not yet seen and the patient dies? First of all, there is no correlation between the severity of cancer and the size of the tumor. In 2012, there was a famous Vietnamese man, Nguyen Duy Hai, who started to grow tumors at the age of 4. By the time he was 30, the tumor in his right leg had reached a staggering 180 pounds! During these 26 years, he slowly lost his mobility, but strangely enough, he didn’t have too many other symptoms and looked relatively normal after the surgery. This tumor looks horrible, but if the location is not in a critical internal organ, it actually poses relatively little risk to life. This huge tumor is almost certainly benign, because if it is malignant, there is no chance that it will grow this big. What is the difference between benign tumor and malignant tumor? –It depends on whether the tumor is metastatic or not. A benign tumor does not metastasize and is a “nail in the coffin”, so as long as the tumor itself is removed by surgery, it is basically cured. Malignant tumors, regardless of their size, have metastasized, possibly in the blood system, in the lymphatic system, or to other organs of the body. Many cancers (such as breast cancer) metastasize generally reach the lymph nodes first, and then follow the lymphatic system to reach other systems. Therefore, lymph node aspiration is often performed for tumor patients in clinical practice, and if there are no tumor cells in the lymph nodes, the patient is at less risk, and the disease can be controlled after chemotherapy and radiotherapy in general. So how does cancer actually kill? First of all, it must be said that there is no definite answer to this question, each patient’s individual condition is different, and the ultimate cause of death is also different. But broadly speaking, it is often related to organ failure, either one organ failure or systemic failure. Tumors, whether malignant or not, whether metastatic or not, may overgrow and compress key organs, for example, brain tumors often compress important nerves and lead to death, lung cancer grows and fills up the space in the lungs, resulting in greatly reduced oxygen exchange capacity in the lungs and eventually death due to functional failure, leukemia leads to depletion of normal blood cells resulting in systemic hypoxia and lack of nutrition, etc. One reason is that one tumor becomes N tumors when it metastasizes, which is naturally harmful. Another reason is that the metastases are often very important places, and the more fatal places are brain metastasis, lung metastasis, bone metastasis and liver metastasis. These three places have another common feature: due to the importance of the organ, surgery is often very conservative and it is difficult to remove the tumor completely. Therefore, if breast cancer is detected early, it is usually fine and the patient can survive for decades after surgery to remove the breast, but if breast cancer metastasizes to the lung or brain, it is very difficult to treat because you cannot remove all the lung or brain. Therefore, you and your parents must go to the hospital for regular medical checkups every year, so that if you find it a few months earlier, you may be able to live a few more decades. Death from cancer is sometimes not caused by the failure of one organ, but by the failure of a system. There are many cancers that, for reasons that are still unknown, cause rapid weight loss and loss of muscle and fat, a process called cachexia. This process has no cure and is irreversible, no matter how much the patient eats or how much protein is infused. Since muscle and fat are essential to the energy supply of the entire body and endocrine regulation, the patient will soon experience system failure. For example, Steve Jobs, a national icon, lived for 8 years after his diagnosis of pancreatic cancer, which is no small miracle, but if you look carefully at the comparison of his before and after photos, you can clearly see that the muscles and fats on his body almost disappeared. In the end, he died due to respiratory failure.