(HealthDay News) — A test used to diagnose lung cancer may not be as reliable in geographic regions where certain lung infections are more common, according to research published in the Sept. 24 issue of the Journal of the American Medical Association.
Stephen A. Deppen, Ph.D., of the Tennessee Valley Healthcare System and Vanderbilt University Medical Center in Nashville, and colleagues conducted a meta-analysis to assess the accuracy of using 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) to diagnose lung lesions in regions with locally-endemic infectious lung diseases. Seventy studies, reporting on a total of 8,511 nodules, 5,105 (60 percent) of which were malignant, were included in the analyses.
The researchers found that, overall, the FDG-PET’s ability to correctly identify people with lung cancer was 89 percent. The test’s specificity was 77 percent in adjusted analysis. The researchers noted that when they examined only geographic areas with a high prevalence of infectious lung diseases, FDG-PET scans had a 16 percent lower average specificity, indicating that the lung diseases common in those regions may have sometimes been mistaken for lung cancer on the imaging tests.
“Knowledge of this reduction in specificity should limit the use of FDG-PET to diagnose lung cancer,” the authors write. They suggested that only institutions with proven expertise in interpreting these scans in geographic areas where lung infections are common should use them for diagnosing lung cancer.