Value of FDG-PET for Lung Cancer Varies By Region

Use of FDG-PET technology to diagnose lung cancer may not be accurate in certain areas of the United States, according to a study published in JAMA.

Researchers from Vanderbilt University in Tennessee and the Tennessee Valley Healthcare System-Veterans Affairs undertook a study to estimate the diagnostic accuracy of FDG-PET for pulmonary nodules suspicious for lung cancer in areas where infections like histoplasmosis or tuberculosis are common, compared with areas where these infections were not frequently found.

The researchers searched MEDLINE, EMBASE, and the Web of Science for lung cancer abstracts published from October 1, 2000 to April 28, 2014. Studies had to include 10 or more subjects to be considered. The researchers included articles reporting information that was sufficient to calculate sensitivity and specificity of the FDG-PET to diagnose lung cancer. Of 1,923 articles found, 70 articles that reported on 8,511 nodules were included in the study. A total of 5,105 (60%) were malignant.

The results showed heterogeneity for sensitivity (87%) and specificity (82%) was observed across the studies. The pooled (unadjusted) sensitivity was 89% and specificity was 75%. “There was a 16 percent lower average adjusted specificity in regions with endemic infectious lung disease (61 percent) compared with nonendemic regions (77 percent),” wrote the authors.

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"The accuracy of FDG-PET for diagnosing lung nodules varied widely from study to study," first author Stephen Deppen, PhD, assistant professor in thoracic surgery, Vanderbilt University, said in a release. "FDG-PET scans had more false positive results and, therefore were less specific in diagnosing lung cancer in regions of the world where infectious lung disease is common in the general population." The authors noted that incorrect findings could lead to unnecessary testing, even lung surgeries.

They concluded that the data do not support the use of FDG-PET for diagnosing lung cancer in endemic regions unless an institution has substantial and proven expertise in FDG-PET interpretation.