Every year, health care providers in the United States discover more than 1.6 million lung nodules in patients. Many are “incidentally detected,” meaning they are found during screening for an unrelated cause. Although 75 to 85 percent of these incidentally detected nodules turn out to be benign, they can pose a diagnostic dilemma for clinicians. For patients with high-risk nodules, it is clear that more invasive testing such as biopsy and even surgery to remove the nodule are appropriate. However, when there’s a low-to-moderate probability of cancer — anywhere from 5 to 65 percent — clinicians may have difficulty deciding which patients should simply be monitored with serial PET or CT scans and which should proceed to more invasive diagnostic testing.

Findings of the multicenter PANOPTIC study, published online by Chest on March 1, 2018, shows that a new biomarker is 98 percent effective at distinguishing benign from malignant lung nodules. The study was led by Gerard A. Silvestri, M.D., a lung cancer pulmonologist at the Medical University of South Carolina who holds the George C. and Margaret M. Hillenbrand Endowed Chair. The biomarker shows promise as a rule-out test for lung cancer in patients with low-to-moderate-risk nodules but is not intended as a rule-in test for patients with higher-risk nodules.