Malignant lesions may not be accurately identified using fludeoxyglucose (FDG) PET scans combined with CT for populations with endemic infectious lung disease, according to a study published in  the Sept. 24 issue of JAMA.

Researchers Stephen A. Deppen, PhD, of the Veterans Affairs Hospital, Tennessee Valley Healthcare System, and Vanderbilt University Medical Center, Nashville, and colleagues conducted a meta-analysis to evaluate the accuracy of FDG-PET combined with CT imaging in detecting disease in regions where it is endemic compared with its accuracy of detection in regions where it is rare.

“These data do not support the use of FDG-PET to diagnose lung cancer in endemic regions unless an institution achieves test performance accuracy similar to that found in non-endemic regions,” wrote the authors.

The study found there was a 16 percent lower average adjusted specificity in regions with endemic infectious lung disease (61 percent) compared with that of non-endemic regions (77 percent).

Knowledge of the FDG-PET/CT performance is “even more critical because the vast majority of indeterminate lung nodules detected through screening are benign,” the authors wrote. This is especially true, they added, if low-dose CT screening became the diagnostic standard.

Lower specificity was observed when the analysis was limited to rigorously conducted and well-controlled studies. In general, sensitivity did not change appreciably by endemic infection status, even after adjusting for relevant factors, the authors said.

The pooled sensitivity was 89 percent and specificity was 75 percent, reported the authors.