The prevention and diagnosis of lung cancer is supposed to be a purely academic issue. However, in China, which has its own characteristics, it is not complimentary. There are many influencing factors, as a result, patients do not get the best prevention and diagnosis and treatment, or even delay the diagnosis and treatment, which is seriously harmful to patients. I. Prevention: Can lung cancer be prevented? Is there any way to prevent it? How much room of activity can a specific individual have to successfully prevent lung cancer? The conclusion is pessimistic. At least now, it is a bit comical to talk about prevention under the toxic atmosphere. Now, the relationship between PM2.5 and even smoking and lung cancer is not yet or not very clear, and the latency period of lung cancer is not even known, and how can we achieve the goal of a lifetime need for clean air in China? How to eliminate the pervasive toxins and pollution? There is little hope. In short, it is nebulous to talk about prevention. The incidence and death rate of lung cancer has jumped to the first place in almost every major city in China. Therefore, the most important prevention issue should be focused on early diagnosis and early treatment. II. Diagnosis 1. Many book knowledge is from the last century, for example, the symptoms of lung cancer, the seventh edition of 2011 National Textbook for Higher Education, Internal Medicine, says that there are five signs and symptoms caused by primary tumors: cough, bloody sputum or hemoptysis, shortness of breath or wheezing, fever, and weight loss. Except for cough, or occasional blood in sputum (not large mouthful of blood), which may be a manifestation of early stage lung cancer, hemoptysis, shortness of breath, wheezing, fever and especially weight loss are all symptoms of middle and late stage. Signs and symptoms caused by intrathoracic extension listed in the book: chest pain, hoarseness, dysphagia, pleural fluid, superior vena cava obstruction syndrome, Horner’s syndrome. More so, if there is already intrathoracic extension, it is more advanced, and if lung cancer is diagnosed by these signs and symptoms, it must not do early diagnosis. Of course, such knowledge is necessary for doctors to know more about the manifestations of lung cancer and not to misdiagnose when patients with middle and late stage lung cancer visit the doctor. However, tumor diagnosis should be as early as possible, and in this spirit, making diagnosis based on the signs and symptoms stated in this book will delay the diagnosis for many patients. This is what often happens in clinical practice nowadays. In fact, the tumor may not be symptomatic at all unless it grows to a certain size or if it does not occur in larger lung segments and lobe bronchi. Clinically, many patients with stage I and II lung cancer can have no symptoms at all or almost no symptoms at all, much less physical signs. In particular, almost all microscopic lung cancers are accidental findings during physical examinations or chest radiographs or CTs for other diseases. Therefore, it should be emphasized that over 45 or 50 years of age should have annual X-rays or CT exams! This is the effective way to detect early lung cancer. 2. The X-ray manifestation of lung cancer described in the book was observed in the 1960s-70s of the last century. “Garden-shaped, garden-like, lobulated, burr…” It should be said that this is the morphology of typical lung cancer. Over time, lung cancer morphology has changed too much. Nowadays, we can often encounter lung shadows of different morphology in clinical practice, which do not fit the above description at all, and the preoperative imaging does not look like lung cancer in any way. “The pathology report is actually lung cancer! In recent years, the so-called “hairy glass-like nodules” have been termed as a result of clinical experience over the years. Many of these nodules, which are not dense, have unclear borders, are not lobulated, have no burrs, and are difficult to distinguish from infections or other medical conditions, are finally confirmed to be lung cancer. Therefore, it is important not to arbitrarily make a benign diagnosis based on past experience, depriving patients of the opportunity for follow-up and timely confirmation of the diagnosis. That would be harmful to people! There is a widely circulated opinion about a specialist doctor in the X-city medical community that patients spend a lot of money, but because of his aging knowledge and stubbornness, he repeatedly misdiagnosed the disease, causing patients to lose the best time for treatment. It is a pity and a pity! 3, for tiny nodules, in the past, if not surgery, often every three months, frequent percutaneous lung puncture biopsies. Even so, there are still delayed cases. The world’s most famous thoracic surgeon, JD Cooper of the United States, once spoke of his personal experience at the 86th annual AATS meeting in North America. His friend had been closely observed for 3 years, including repeated needle aspiration biopsies, and was found to have slightly enlarged and operated on immediately, by which time there was already a mediastinal lymph node metastasis. Needless to say, the cure rate and even the 5-year survival rate are going to be greatly reduced! Today, thoracoscopic techniques are quite mature, and small nodules and hairy glass-like nodules in the lungs should be actively subjected to thoracoscopy or other forms of biopsy or surgery. Only with early detection, early diagnosis and early surgical treatment is it possible to achieve radical cure.