A multi-society, comprehensive, systematic review concluded that screening 10,000 individuals at elevated risk for lung cancer with annual low-dose CT will prevent approximately 30 lung cancer deaths but cause approximately three radiation-induced cancers, typically 10 to 20 years later (Bach PB. JAMA. 2012;307:2418-2429). However, a structured program that minimizes further imaging and biopsies is crucial. The radiation dose of the screening low-dose CT is low (less than half the dose of annual environmental background radiation), but the radiation from subsequent diagnostic imaging studies may be substantial. This is particularly concerning because low-dose CT frequently detects small nodules.
Nevertheless, lung cancer screening studies have shown that we can manage this well without excessive imaging, but structure is crucial. A management algorithm can effectively soothe the anxiety stirred up by the many small findings and counter the push from anxious patients for more imaging or invasive procedures than what is really needed. The keys to effective implementation of screening are the thoughtful, judicious evaluation of the low-dose CT and communication of this interpretation with the patient — not the low-dose CT scan itself or jumping to aggressive intervention. Furthermore, selection of individuals who are clearly at elevated risk also is crucial; extending screening to lower-risk individuals exponentially reduces the benefits, and screening younger individuals increases the risks for radiation exposure over time.
The evidence shows that lung cancer screening, done in an organized program and involving appropriately selected patients, has benefits that outweigh the risks of radiation exposure. The outcomes of unorganized screening (ie, loosely selected individuals, scans interpreted by general radiologists, findings managed by primary care physicians) have not been defined, but they are likely to be highly variable and much less positive. Therefore, all the thoracic societies and the US Preventive Services Task Force recommend that screening be done in a structured program. In such a setting, the risks of radiation exposure are dwarfed by the reduction in lung cancer deaths.