Conference Coverage

Next-gen genomic test plus bronchoscopy may improve lung nodule management



– The use of a next-generation genomic test may enable improved management of patients with pulmonary nodules when results of bronchoscopy are inconclusive, results of a recent clinical validation study suggest.

Dr. Peter J. Mazzone, CHEST editor in chief

Dr. Peter J. Mazzone

The Percepta Genomic Sequencing Classifier (GSC) was able to up- and down-classify probability of malignancy for a considerable proportion of nondiagnostic bronchoscopies in the study, Peter J. Mazzone MD, FCCP, reported at the annual meeting of the American College of Chest Physicians.

The test is seen as complementary to bronchoscopy, improving the sensitivity of bronchoscopy overall and showing a combined sensitivity of greater than 95% in low- and intermediate-risk groups, according to Dr. Mazzone.

While the clinical utility of this genomic test needs to be further tested, the eventual goal is to improve clinician decision making when bronchoscopy results don’t clearly classify nodules as malignant or benign, Dr. Mazzone said in an interview.

“In that situation, you’re often left wondering, ‘what should I do next? Can I just watch this, and see if it grows and changes, or do I have to be even more aggressive – do another biopsy, or have a surgery to take it out?’ ” he explained. “So the test hopes to help make a more informed decision by further stratifying those patients as being quite low risk and maybe safe to follow, or quite high risk and maybe you should be considering more aggressive management.”

The GSC improves on the performance of an earlier molecular test, the Percepta Bronchial Genomic Classifier, which uses a brushing of bronchial epithelium to enhance nodule management in smokers, according to the researcher.

The next-generation GSC uses 1,232 gene transcripts from whole-transcriptome RNA sequencing, along with clinical factors, to help with nodule diagnosis, he said.

To establish the diagnostic accuracy of the GSC, Dr. Mazzone and colleagues evaluated data on 412 patients from three independent cohorts, all of whom had bronchoscopies for lung nodule evaluation that were nondiagnostic. Of those patients, 5% had nodules that physicians had deemed as low probability of malignancy prior to bronchoscopy, 28% deemed intermediate risk, and 74% high risk.

They found that the Percepta GSC down-classified the low–pretest risk patients with 100% negative predictive value (NPV) and down-classified intermediate–pretest risk patients with a 91.0% NPV, Dr. Mazzone reported, while patients with intermediate pretest risk were up-classified with a 65.4% positive predictive value (PPV) and patients with high pretest risk were upclassified with a 91.5% PPV.

The proportion of patients reclassified was about 55% for the low-risk group, 42% for the intermediate-risk group, and 27% for the high-risk group, according to the report at the meeting.

These results suggest the Percepta GSC could help in the “sticky situation” where a bronchoscopy result is inconclusive, Dr. Mazzone told attendees.

“When a bronchoscopy is recommended, despite fantastic advances in navigation systems to get to those nodules, we often come back without a solid answer, and that leaves the clinician in a bit of a predicament,” he said in a late-breaking clinical trial presentation.

Dr. Mazzone provided disclosures related to Veracyte, Exact Sciences, SEER, Tencent, and PCORI (research support to institution).

SOURCE: Mazzone PJ et al. CHEST 2019, Abstract. doi: 10.1016/j.chest.2019.08.307.

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