Small lung nodules ≠ lung cancer! Correctly deal with abnormal lung signals

Author: Zhi Xiuyi, Chief Physician of Beijing Tsinghua Chang Gung Hospital affiliated to Tsinghua University

Reviewer: Zhang Yu, researcher at Chinese Center for Disease Control and Prevention

Lung cancer is the malignant tumor with the highest incidence and mortality rate in the world. The importance of its prevention and treatment is self-evident. According to official data, cancer has become the main cause of death among urban residents in my country, and lung cancer ranks first among all types of cancer. In the past 30 years, the mortality rate of lung cancer has increased by 465%, surpassing liver cancer to become the number one killer of malignant tumors in my country.

The classification of lung cancer is mainly based on the location and pathological type of the tumor. According to the location, lung cancer can be divided into central lung cancer and peripheral lung cancer. The former is located in the trachea or bronchi, and the latter is located inside the lung lobes. In terms of pathological type, lung cancer is mainly divided into two categories: small cell lung cancer and non-small cell lung cancer. Small cell lung cancer grows rapidly and is prone to metastasis, accounting for 15%-20% of lung cancer cases, and is highly correlated with smoking; while non-small cell lung cancer includes lung adenocarcinoma, lung squamous cell carcinoma and large cell carcinoma, accounting for about 80% of all lung cancers, among which the incidence of lung adenocarcinoma has increased in recent years, especially among non-smokers.

Figure 1 Original copyright image, no permission to reprint

The staging of lung cancer is crucial for the selection of treatment options. Lung cancer is divided into stages I, II, III, and IV based on factors such as the size of the tumor, whether it invades the hilar lymph nodes, and whether there is mediastinal lymph node metastasis. Stage I lung cancer usually refers to a small tumor (≤3cm) with no lymph node metastasis; stage II has hilar lymph node metastasis; stage III further extends to the mediastinal lymph nodes; and stage IV indicates distant metastasis, such as brain metastasis, bone metastasis, etc.

Figure 2 Original copyright image, no permission to reprint

When it comes to risk factors and early detection of lung cancer, smoking is undoubtedly one of the main causes. my country has a large group of smokers, and exposure to secondhand smoke is also widespread. In addition, population aging, bad living habits, environmental pollution (including air pollution, indoor pollution, etc.), psychological pressure, etc. are also important factors in the high incidence of lung cancer. Among them, the "five airs" are particularly worthy of attention: air pollution, tobacco smoke, kitchen fumes, harmful substances in house decoration materials, and psychological pollution.

In order to achieve early detection of lung cancer, chest CT screening is currently recommended, especially for high-risk groups, such as those over 45 years old with a long history of smoking. Chest CT can detect lung cancer when the lesion is still small and there are no obvious symptoms, which is crucial to improving the success rate of treatment. For central lung cancer, early diagnosis may require fiberoptic bronchoscopy.

With the popularity of physical examinations and lung cancer screening programs, more and more people have found small lung nodules on CT scans, which often causes people to worry. However, when lung nodules are first found on CT, there is no need to panic. This is because we cannot determine how long these nodules have existed and what their nature is.

At present, the medical community has formed a series of expert consensus to guide the treatment of lung nodules of different sizes (such as less than 1 cm, 1 cm to 3 cm, etc.). Even if a small lung nodule is found through chest CT, it should not be decided to undergo surgery immediately. In fact, in major hospitals in some large cities, after surgery for such nodules, it was found that about half of the cases were not lung cancer.

Lung nodules may be caused by a variety of reasons, such as inflammation or old lesions, which usually do not require surgical intervention. In addition to chest CT examination, tumor marker detection, lung cancer-related antibody detection, and gene sequencing can also be combined to comprehensively evaluate the nature of the nodules.