In recent years, “lung nodule” has begun to become a hot search term on major medical websites, which is an imaging diagnosis. Lung shadows with a diameter of less than 3cm found on chest radiographs or chest CT are called lung nodules, of which those with a diameter of less than 1cm are called pulmonary nodules, and those with a diameter of less than 0.5cm are called micronodules. With the popularization of the awareness of “early diagnosis and early treatment” of cancer and the improvement of CT imaging technology, more and more lung nodules begin to be found. Overseas survey data show that the detection rate of lung nodules in 18-24 year olds is more than 1 per thousand, and as the age of the population grows, the detection rate gradually increases, and the detection rate in 55-64 year olds is close to 2%. Considering factors such as air pollution and dietary habits, the incidence of lung nodules in our population may be even higher. Ground-glass shadow of the lungs is a different concept from lung nodules and lung cancer, and there is no necessary connection between them. The difference between the concepts of shadow and nodule is that shadow is a generalized reference to the shadows found by imaging, with unlimited size and shape, while nodule refers to the round-like lesions within 3 cm with clear boundary. The imaging manifestation of early lung cancer is small nodular lesions in the lungs, but small nodules in the lungs are not equal to lung cancer. When we find out that there are small nodules in the lungs, we must be full of panic and doubt. Are small nodules in the lungs lung cancer? What kind of disease is small nodules in the lungs? Are small nodules in the lungs equal to lung cancer? Since about 60%-70% of nodules are benign and about 30%-40% of nodules are malignant, do not be alarmed. In terms of probability, the vast majority of lung nodules found for the first time are benign (inflammation, tuberculosis, scarring, lymph nodes, etc.), and less than 20% are likely to be malignant. Secondly, even in the case of lung cancer, the vast majority of cases are in the early stages, and with appropriate treatment, the patient’s normal life expectancy will hardly be affected. Therefore, from the point of view of early diagnosis and treatment of cancer, the discovery of lung nodules is a lucky thing, and the vast majority of them end up in a comedy, and excessive worries are mostly proved to be superfluous in the end. At this moment, the more important thing to do is to find a good doctor who can help you with his expertise to turn the happy ending into a reality at minimal cost. In order to rule out lung cancer, there are 3 things that need to be accomplished: 1. Clarify whether you are at high risk for lung cancer, which is crucial when your doctor evaluates the benignity or malignancy of the nodule! These high-risk factors include: the patient’s age, lifestyle habits, long-term environment, past health status, and genetic information. For example: Are you a smoker or have you ever smoked? Any history of exposure to carcinogens (asbestos, radon, radium, etc.)? Have you had other cancers? Any other lung diseases such as emphysema or pulmonary fibrosis? Have parents, brothers and children ever had cancer? It is important to note that being at high risk does not mean that a lung nodule is necessarily lung cancer, nor does being at low risk mean that it is not; it is really a matter of probability. Characteristics of lung nodules On thin-layer CT, they are divided into the following three types according to the density size: (1) Pure ground-glass nodules Pure ground-glass nodules with an image presentation like frosted glass. (2) Partially solid ground-glass nodules, which look like a ruffled egg from the image. Partially solid ground-glass nodules tend to be invasive carcinomas with a higher degree of malignancy. (3) Pure solid nodule Impact suggests a solid, dense lesion similar to an individually isolated yolk. What should be done after characterization of a lung nodule? 1. When the imaging is clearly benign or the diameter of the lesion is less than 6 mm, it does not require any further treatment 2. When the lesion has a higher likelihood of being a lung cancer and is estimated to be more malignant, a timely biopsy or surgery is needed to make a definitive diagnosis. Some lung cancers with higher malignancy have characteristic manifestations on CT, such as larger size, more solid components, active growth of tumor and blood vessels, etc. In this case, timely biopsy or surgery is needed to confirm the diagnosis. Timely surgical biopsy in such cases can avoid the risk of tumor metastasis during the waiting process. If it is difficult to characterize the tumor at the moment, must it be “timely” surgically removed? A: Observe and follow up for a period of time, and then perform surgery after confirming the diagnosis of lung cancer. In the past, surgical resection used to be the first choice of treatment for lung nodules, and the idea of “timely and complete removal of lesions” was widely accepted by doctors and patients for some time. However, with the deepening of the understanding of lung nodules, it has been found that a considerable portion of the resected lung nodules are benign or low-grade malignant lung cancers. Compared with patients who do not undergo surgery, surgical patients do not benefit in terms of survival from the removal of the lesion; on the contrary, the removal of lung tissue often affects the patient’s quality of life or creates problems for possible future lung surgery. Therefore, nowadays, the indications for lung nodule surgery are becoming more and more stringent, and more patients will wait for a period of time before surgery or biopsy, repeat the CT examination, and improve the diagnostic accuracy by observing the changes of the nodules, which is medically called “follow-up diagnosis”. This is like judging a person’s goodness or badness based on the first time you meet him or her, which often leads to mistakes. As the saying goes, “time and time again will tell”, if we observe for a period of time, the chance of making a mistake in judgment will be greatly reduced. There are more than a dozen combinations of follow-up plans, depending on the varying chances of a lung nodule being lung cancer, which need to be developed by a medical professional. What to do if you have a ground glass lung nodule Surgery? Ignore? Injections and medications? This is something that many patients struggle with. 1.Pure pulmonary ground glass nodules 1) Recommendation: for non-solid (pure ground glass) nodules ≦8mm, according to the patient’s wishes and clinical judgment, annual CT examination and monitoring. 2) Recommendation: for non-solid (pure ground glass) nodules ﹥8mm, review the CT in half a year, and the foci have not disappeared or shrunken, and then, according to the patient’s wishes and clinical judgment, review annually or elective surgery. 3) Recommendation: for non-solid (pure ground glass) nodules >8mm, review CT within half a year, and then review annually or selective surgical treatment. 2.Mixed pulmonary ground-glass nodules 1) Recommendation: Partial nodules ≦8mm, reassessment by low-dose spiral CT in 3 months, if the nodules are stable, annual review or selective surgical treatment according to the patient’s wishes and clinical judgment. (2) Recommendation: For partial nodules >8mm, with malignant signs on imaging and risk factors, surgery is recommended. Whether follow-up will delay the disease Patients often have this concern: “Let me review in 3 months, if it is really a malignant tumor, will it spread and metastasize?” The answer is no. If a small lung nodule found for the first time during a physical examination is judged to have a high likelihood of malignancy, the doctor will definitely recommend surgery as soon as possible. If the nature of a moment is not easy to determine, and clinically there is no better means to help diagnosis, doctors often recommend antibiotic treatment and review, or review after 3 months to understand the changes in the nodule. Tumor growth has a doubling time, generally considered to be 3 months to 12 months. During the review process, if the nodules remain unchanged for several years, or gradually shrink, or rapidly increase in size in a short period of time, it often suggests a benign lesion, such as inflammation. It is the small nodules or ground-glass shadows that need to be guarded against as they slowly increase in size or solidify with increased density. For small nodules less than 1cm, even if they are malignant and the diameter increases by a factor of 1, they are still in the early stage of lung cancer and can be cured by surgery, and generally do not need later radiotherapy. For single nodule, if there is no obvious change in the size and density of the nodule after two years of follow-up, the nodule is considered stable and can be terminated for review. However, in the case of multiple nodules in the lungs, the total observation period needs to be extended to five years. Treatment means of small nodules in the lungs Minimally invasive surgery: minimally invasive thoracoscopic surgery, less traumatic, mature technology, easy to accept by patients, belongs to the classic program. CT-guided radiofrequency ablation: done in the CT room, no need to go into the operating room or general anesthesia, operated by professional doctors. Stereotactic radiotherapy: it is a better alternative therapy for patients with poor tolerance of surgery, poor lung function and high risk factors. However, the number of enrolled cases is small, the follow-up time is short and controversial, and the cancer is prone to recur if a cancer cell is missed. Chemotherapy: It is limited to patients with lymphatic metastasis from small nodule lung cancer and can be adjuvant to chemotherapy. Chinese medicine supportive therapy: Chinese medicine can increase immunity. Immunotherapy is less available at present and there are day-to-day changes. Targeted drug therapy: it must be taken with clear gene mutation. The timing and types of drugs are being explored and are currently limited to patients with localized recurrence and metastases.