§ Lung cancer screening refers to cancer screening strategies used to identify early lung cancers before they cause symptoms, at a point where they are more likely to be curable. Lung cancer screening is critically important because of the incidence and prevalence of lung cancer. More than 235,000 new cases of lung cancer are expected in the United States in 2021 with approximately 130,000 deaths expected in 2021. In addition, at the time of diagnosis, 57% of lung cancers are discovered in advanced stages (III and IV), meaning they are more widespread or aggressive cancers. Because there is a substantially higher probability of long-term survival following treatment of localized (60%) versus advanced stage (6%) lung cancer, lung cancer screening aims to diagnose the disease in the localized (stage I) stage. However, lower socioeconomic areas, where income inequality and lower education are social determinants that contribute to preventing adequate lung cancer screening, resulting in a sense of delayed lung cancer screening and treatment, places an additional increase to the mortality rate. Results from large randomized studies such as the U.S. National Lung Screening trials (NLST) have recently prompted a large number of professional organizations and governmental agencies in the U.S. to recommend lung cancer screening in select populations now. The three main types of lung cancer screening are low-dose, computerized tomographic (LDCT) screening, chest x-rays, and sputum cytology tests. Currently multiple professional organizations, as well as the United States Preventive Services Task Force (USPSTF), the Centers for Medicare and Medicaid Services (CMS) and the European Commission's science advisors concur and endorse low-dose, computerized tomographic screening for individuals at high-risk of lung cancer.
Findings Most cancers found in lung cancer screening programs arise from solid or part-solid nodules; only very few from non-solid nodules. Most cancers (over 90%) were diagnosed in nodules with baseline volume ≥300 mm3. Larger nodules (≥300 mm3) are more often located in the upper lobes.
Guidelines
The definition of who is considered to be at sufficiently high risk to benefit from lung cancer screening varies according to different guidelines.
U.S. Preventive Services Task Force The 2021 U.S. Preventive Services Task Force guidelines recommend annual screening for lung cancer with low-dose computed tomography in adults aged 50 to 80 years who have a 20 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has either not smoked for 15 years, or develops a health problem that substantially limits the person's life expectancy or the ability or willingness to have curative lung surgery.
National Comprehensive Cancer Network (NCCN) The National Comprehensive Cancer Network (NCCN) suggests screening for two high risk groups. Group 1 guidelines include 55–77 years of age, 30 or more pack years of smoking and has quit within the past 14 years, and are a current smoker. Group 2 includes those 50 years of age or older, 20 or more pack years of smoking, and other risk factors excluding second-hand smoke. Other risk factors include:
contact with specific carcinogens: radon, arsenic, beryllium, cadmium, chromium, nickel, asbestos, coal smoke, soot, silica, or diesel fumes; personal history of cancer; family history of lung cancer; or history of COPD or pulmonary fibrosis.
European Commission In 2022, the European Commission's Scientific Advice Mechanism concluded that "there is a strong scientific basis for introducing lung screening for current and ex-smokers using the latest technologies, such as low-dose CT scanning".
Risks
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