Key Points
• In this retrospective study, researchers compared the utility of circulating tumor DNA (ctDNA) and solid tumor biopsy in non-small cell lung cancer. They assessed the usefulness of ctDNA in the identification of mutations, survival, tumor evolution, and concordance with matched tissue samples with regard to 32 genes.
• In total, the researchers identified 473 ctDNA samples, of which 177 had at least one actionable mutation per therapies approved for NSCLC by the FDA.
• The overall concordance rate was 93.8%. Notably, concordance rates varied from 50% to 55% in early-stage cancers and 64% to 83% in late-stage and metastatic cancer. The authors attributed the lower concordance in early-stage NSCLC to a lack of sensitivity to DNA shedding in early tumors, along with low overall tumor mutational burden. They also noted that more gene and actionable gene mutations were discovered in ctDNA compared with those in tissues biopsies in matched samples, a finding that aligns with previous research.
• According to the authors, “ctDNA captured clinically useful, actionable, and dynamic information by identifying targetable mutations regardless of patients’ clinical status. Thus, ctDNA can provide complementary information to tissue biopsies in cancer management and surveillance, and offer additional targetable opportunities beyond when tissue biopsies are not attainable.”
• The current study had several limitations. For instance, most of the patients had advanced versus early-stage NSCLC, thus making the findings less universal. Furthermore, because this study relied on retrospective data from one center, which may have lacked sufficient NSCLC diversity. Moreover, certain cases needed to be excluded due to missing survival data.