Early screening methods for lung cancer

Lung cancer screening mainly includes X-rays and sputum cytology. With the rapid development of imaging technology and molecular biology technology, not only has the development of basic research on lung cancer been greatly promoted, but also powerful tools have been provided for lung cancer screening, including low-dose spiral CT, molecular markers, 8F-fluoro-deoxy-glucose (FDG) positron emission tomography (PET) and fluorescent fiber bronchoscopy.

Low-dose spiral CT reduces the amount of X-ray radiation from the CT tube due to the reduced current, which not only reduces energy consumption, reduces costs and increases the life of the X-ray tube, but also reduces the amount of radiation to the human body to ensure that the patient's body is not harmed, so it is suitable for census needs. Low-dose spiral CT can detect lung cancer about 4 times more than chest X-ray. However, CT diagnosis also has its shortcomings, such as high prices, high nodule detection rate, but difficult qualitative identification, which requires the combination of other methods, and low early detection rate of central lung cancer.

The research and screening of tumor markers has become a hot topic in the early diagnosis of lung cancer. At present, several types of serum markers such as carcinoembryonic antigen (CEA), carbohydrate antigen (CA19-9), and cytokeratin 19 fragment (cyfra-19) have been widely used in the clinical diagnosis of lung cancer, but their sensitivity and specificity are low and cannot be used for screening of high-risk groups for lung cancer. Molecular genetic changes can provide a series of molecular biological markers for the early diagnosis of lung cancer. The molecular pathological abnormalities related to lung cancer reported so far include: chromosomal aberrations and anomalous ploidy; abnormal telomerase activity; allele deletions of 3p, 9p, 8p, and 17p; p53, ras gene mutations; p16, abnormal methylation of MGMT genes, etc. Therefore, the use of non-invasive or minimally invasive samples such as sputum, daytime bronchoalveolar lavage, and peripheral blood to detect early molecular events of lung cancer has become a research hotspot.