Molecular Testing in Non-Small Cell Lung Cancer

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A long list of genetic alterations has emerged in non-small cell lung cancer (NSCLC), several of which are targetable with an approved therapy. As a result of the high number of actionable alterations, Roy S. Herbst, MD, PhD, genetically profiles every patient prior to first-line therapy. This testing should move beyond EGFR and ALK, explains Anne S. Tsao, MD, to include ROS1, HER2, BRAF, KRAS, and RET mutations, as clinical trials are available targeting these mutations.

The presence of an actionable mutation dramatically impacts treatment, Herbst notes. Targeted therapies are generally more efficacious and tolerable compared with chemotherapy. The importance of testing is underscored by the value of obtaining adequate tissue. In many situations, fine needle biopsies may not collect enough tissue for adequate testing, warranting a core biopsy or excisional biopsy, Herbst suggests.

In addition to tissue-based assays, a number of less invasive tests are rapidly becoming available. VeriStrat is a clinically validated serum test for patients with advanced NSCLC that is meant to help determine if treatment with a TKI is optimal. The test is predictive of which patients will be likely to have good or poor outcomes after treatment with TKIs. The rapidity of test results with VeriStrat, less than 72 hours, allows for quick treatment decisions.

Thomas E. Stinchcombe, MD, states that he uses Veristrat as more of a “negative selector” based on the PROSE trial efficacy data. In this analysis, VeriStrat status was predictive of differential overall survival benefit for erlotinib versus chemotherapy in the second-line setting. In the VeriStrat poor group, patients responded more favorably to chemotherapy than erlotinib. In the good group, there was not a significant difference between outcomes between the two treatment arms (HR = 1.09).