Update on the Methods of the U.S. Preventive Services Task Force: Insufficient Evidence

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Domain	Information
Potential preventable burden	About 170,000 new cases of lung cancer are diagnosed each year in the United States. About 160,000 deaths per year are attributable to lung cancer. Currently, lung cancer has an appreciable 5-year survival rate only if it is diagnosed at an early stage.
Potential harms	Suspicious lung lesions are identified by CT screening in about 13% of at-risk individuals, such as ever-smokers. About 10% of these lesions found on an initial screen and 5% of those found on annual screening turn out to be lung cancer.²⁶ Evaluation of suspicious lung lesions may require additional imaging tests and some patients may need a thoracotomy to rule out lung cancer. Waiting for a definitive diagnosis after the finding of a suspicious lesion may cause anxiety. Screening CT delivers exposure to 0.3 to 0.55 milliSieverts of radiation, which is the equivalent of ~2 chest x-rays ²⁷ or 1-2 mammograms.²⁸
Costs	The costs of creating the infrastructure to deliver this service to all smokers and ex-smokers would be large. Helical CT takes 30 minutes of patient time and 10 minutes of technician time.²⁹ Provision of this service may allow for less time for provision of preventive services that have proven value (opportunity costs).
Current practice	Screening for lung cancer screening with helical CT is not widespread.