FNAs may produce too many false negatives. Follow up imaging suggested.
Fine needle biopsies (FNA) for suspicious lung nodules may produce false negatives and should be followed by an additional CT scan, according to research published in the latest issue of Journal of Thoracic Oncology.
Researchers from the Weill Cornell Medical College and Mount Sinai Hospital in New York City investigated the results from 170 patients who underwent an FNA biopsy that was found to be benign and found with CT follow up that 18 of these results were false negatives, 152 were true negatives.
There were several factors that associated with false negative results, said the researchers. These include false negative nodules being significantly larger than true negative nodules (mean, 27 mm versus 17 mm, p = 0.04), fewer imaging adjustments per needle pass (4.5 versus 6.4, p = 0.01), a higher proportion in whom the needle tip was not documented within the lesion (24% versus 5%, p =0.04), and a higher pneumothorax rate at any point during the procedure (50% versus 22%, p =0.04). There was also the lack of positive cultures.
When these variables were considered jointly, pneumothorax, solitary nodule, and the radiologist who performed the procedure were significant predictors of false negative results.
“A benign FNA biopsy result should have the procedure reviewed to ensure that results are reliable,” the researchers concluded.