The Role of Circulating Tumor DNA in Lung Cancer: Mutational Analysis, Diagnosis, and Surveillance Now and into the Future.

OPINION STATEMENT: Isolation and analysis of circulating tumor DNA (ctDNA) have emerged as an effective and promising tool for genomic profiling in non-small cell lung cancer. Analysis of ctDNA can be particularly useful in situations where tissue biopsy is not safely obtainable due to poor physical condition or inaccessible tumor biopsy location. In addition to identifying oncogenic driver mutations which can be treated with targetable therapy in the treatment naïve advanced non-small cell lung cancer (NSCLC) setting, ctDNA is being utilized in novel ways including monitoring during an advanced NSCLC patient's treatment course (real-time monitoring), determining mechanisms of resistance and, lastly, as a tool to identify minimal residual disease in early-stage NSCLC. Recent research demonstrates that ctDNA testing can provide a useful adjunct to tissue genotyping in NSCLC. Utilization of ctDNA into routine clinical practice for NSCLC should be strongly considered.