National lung screening trial -> 2年後…33%用CT查的人會有false positive result, 有7%會做invasive study, 只有1-2%是true positive

Risk for False-Positive Lung Cancer Screening Is Substantial

一年做一次LDCT的false positive rate 是21%，兩年後是33%

Nine percent of patients with false-positives on computed tomography required invasive testing.

Despite lack of proven efficacy, lung cancer screening has been widely promoted. In the ongoing National Lung Screening Trial (NLST), about 50,000 current or former smokers have been randomized to screening by either chest x-ray or computed tomography (CT).

In a preparative feasibility study for the NLST, 3318 current or past smokers (age range, 55–74) were randomly assigned to receive annual chest radiography or annual low-dose CT. A false-positive was defined as a positive test result followed by a negative completed work-up or no diagnosis of lung cancer within 12 months. After two screening tests 1 year apart, risk for a false-positive result was 15% for participants in the chest radiography group and 33% for those in the CT group. Four percent of those with false-positive chest radiographs and 7% of those with false-positive CT scans underwent at least one invasive procedure as a result. Overall, 1% to 2% of participants had true-positive test results.

Comment: Lung cancer screening with CT scan (or chest radiography) has theoretical but unproven benefits and substantial proven harms. If screening is eventually proven to reduce lung cancer–specific mortality, we will need to understand better the ramifications of false-positive results.

— Richard Saitz, MD, MPH, FACP, FASAM

Published in Journal Watch General Medicine May 25, 2010
Citation(s):

Croswell JM et al. Cumulative incidence of false-positive test results in lung cancer screening: A randomized trial. Ann Intern Med 2010 Apr 20; 152:505.

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* Medline abstract (Free)

https://docs.google.com/fileview?id=0B278nGJMQBk7ZGJmMWJiYTgtZjJjNC00MTY1LTg2YTEtZmU3M2VjMmIwNzM2&hl=zh_TW

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