Lung cancer is one of the most common malignant tumors in China, and its mortality rate ranks first in cancer deaths, whether in urban or rural areas, in men or women. So what exactly is the relationship between lung cancer and lung nodules? Why has the incidence of lung nodules increased year by year in recent years? What should be done when lung nodules are detected? Next, we will explain these questions one by one. Pulmonarynodule (PN) is a round or irregular shaped lesion with a diameter of less than or equal to 3 cm in the lung, which can be single or multiple, with clear or unclear borders. Lung nodules with different densities have different probability of malignancy. There are two major categories of lung nodules based on nodule density: one is solid nodule; the other is sub-solid nodule, including part-solid nodule and groundglass nodule (GGN). So what exactly is the relationship between lung cancer and lung nodules? What are the cautions? Lung nodules are divided into benign nodules and malignant nodules, among which malignant nodules are usually diagnosed as lung cancer after puncture cases or pathology after surgery. According to the report of American Cancer Research Center, the incidence of benign lung nodules accounts for about 70% of the total number of lung nodules, especially nodules less than 3mm in diameter, and the malignancy rate is about 1%, so we should not think it is lung cancer when we hear nodules. Normally, we consider 8mm lung nodules as an important middle point in clinical practice. For nodules >8mm, we usually recommend close observation and follow-up, or even pathological sampling if available. The degree of benign and malignant lung nodules is related to the shape of the nodules and the 3D reconstruction rate of the nodules on CT images; the more regular the morphology, the higher the benignity, and the more lobar, polygonal and irregular the malignancy. Of course, we need to judge these by doctors who are specialized in imaging and tumor-related specialists. 4, the degree of growth of lung nodules, usually, the faster the nodules grow within a certain period of time, the higher the possibility of malignancy; in 2 or 3 years basically no change, the higher the possibility of benign, of course, here refers to the small nodules <8mm. 5. Pulmonary nodules with hairy glass-like changes + solid changes in imaging should be paid close attention to, and the degree of malignancy will be higher in this case. 6, smoking history, plus the incidence of lung nodules in people with a family history of tumors may be higher, to pay attention to the necessary examination, mainly low-dose chest CT screening Why has the incidence of lung nodules increased year by year in recent years? First, it is the progress of our national medical level, the physical fitness of workers, and the popularity of health knowledge. Second, it is the improvement and convenience of examination means, the original is mainly to check the chest X-ray, now low-dose CT examination is very convenient. Thirdly, cases that could not be detected by X-ray can now be detected in time. Fourthly, the influence of environmental carcinogenic factors, such as haze, pollution of living environment, smoking, etc., may be the risk factors. What should I do if I find out lung nodules? Be sure to go to the oncology and respiratory departments of regular hospitals to seek professional recognition for evaluation.