Noninvasive tests may be superior alternative to detecting lung cancer

Guardant360, a liquid biopsy test, identified non-small cell lung cancer (NSCLC) biomarkers at a rate comparable to standard-of-care tissue genotyping tests but with quicker turn-around time, according to results of the Noninvasive versus Invasive Lung Evaluation (NILE) study, presented at the American Association for Cancer Research (AACR) Annual Meeting 2019 in Atlanta, GA.

“Tissue biopsy-based tests are invasive, can have serious complications, are time-consuming, and the specimens are often inadequate to test for all the relevant mutations,” said Vassiliki A. Papadimitrakopoulou, MD, professor, Department of Thoracic Head and Neck Medical Oncology, Division of Cancer Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX. “Our study shows that Guardant360 test results can be obtained in about a week, are reliable, and in some respects a better alternative to the traditional tissue testing in ensuring guideline-complete molecular testing for all patients.”

Researchers of the NILE study assessed whether Guardant360, a liquid biopsy test that uses cell-free tumor DNA in blood, can detect all seven guideline-recommended predictive biomarker mutations (EGFR, ALK, ROS1, BRAF, RET, MET, ERBB2), as well as one prognostic biomarker mutation (KRAS), at the same speed as current tissue genotyping tests. This prospective trial involved 282 patients with newly diagnosed advanced NSCLC.

At least one of the tested biomarkers was identified in 60 patients via tissue-based tests. The addition of Guardant360 upped the rate of detection by 48%, including patients whose samples were negative by tissue, untested, or lacked enough material for the tissue-based tests.

Notably, cfDNA test results of four biomarkers (EGFR, ALK, ROS1, BRAF) jibed with tissue-based test results, yielding a positive-predictive value of 100%. These four biomarkers have FDA-approved drugs.

Turn-around time for Guardant360, which was defined as time from test order to final results, took a median of 9 days compared with a median of 15 days for tissue-based testing.

In another recent study, other investigators found that only 8% of patients with NSCLC receive guideline-recommended testing. Thus, the majority of these patients—as well as their clinicians—lack important information needed for clinical decision-making, according to Dr. Papadimitrakopoulou.

The NILE study did have some limitations. First, the liquid biopsy test was compared with a current standard-of-care tissue genotyping test instead of a tissue-based next-generation sequencing test. Second, the study results apply only to the Guardant360 test and not other liquid biopsy tests.

Despite these limitations, Dr. Papadimitrakopoulou noted that “these findings should give confidence to oncologists to trust Guardant360 as a testing option for treatment selection in NSCLC patients.”

This study was funded by Guardant Health.