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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. Screening studies for lung cancer have only been done in high risk populations, such as smokers and workers with occupational exposure to certain substances. Results from large randomized studies have recently prompted medical authorities to reverse their previous position and now recommend lung cancer screening in select populations. For individuals with high risk of developing lung cancer, computed tomography (CT) screening can detect cancer and give a person options to respond to it in a way that prolongs life. This form of screening reduces the chance of death from lung cancer by an absolute amount of 0.3% (relative amount of 20%). High risk people are those age 55-74 who have smoked a pack of cigarettes daily for 30 years including time within the past 15 years.〔 CT screening is associated with a high rate of falsely positive tests which may result in unneeded treatment. For each true positive scan there are more than 19 falsely positives scans. Other concerns include radiation exposure〔 and the cost of testing along with the follow up of tests.〔 Research has not found two other available tests - sputum cytology or chest radiograph (CXR) screening tests - to have any benefit. Screening studies for lung cancer have only been done in high risk populations, such as smokers and workers with occupational exposure to certain substances. In the 2010s recommendations by medical authorities are turning in favour of lung cancer screening, which is likely to become more widely available in the advanced economies. In December 2013 the U.S. Preventive Services Task Force (USPSTF) changed its long-standing recommendation that there is insufficient evidence to recommend for or against screening for lung cancer to the following: "The USPSTF recommends annual screening for lung cancer with low-dose computed tomography in adults ages 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery".〔(【引用サイトリンク】title=Lung Cancer Screening )〕 Another US guideline recommendation is very similar, but with a cut-off at age 74.〔 The English National Health Service was in 2014 re-examining the evidence for screening. ==Risks of Screening== CT screening is associated with a high rate of falsely positive tests which may result in unneeded treatment.〔 For each true positive scan there are more than 19 falsely positives scans.〔 Other concerns include radiation exposure and the cost of testing along with the follow up of tests.〔 False reassurance from false negative findings, overdiagnosis, short term anxiety/distress, and increased rate of incidental findings are other risks. Radiation exposure from repeated screening studies could actually induce cancer formation in a small percentage of screened subjects, so this risk should be mitigated by a (relatively) high prevalence of lung cancer in the population being screened.〔 Research has not found two other available tests - sputum cytology or chest radiograph (CXR) screening tests - to have any benefit.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lung cancer screening」の詳細全文を読む スポンサード リンク
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