Personalized, tumor-informed, circulating tumor DNA assay for detecting minimal residual disease in non-small cell lung cancer patients receiving curative treatments

Background: Circulating tumor DNA (ctDNA) has emerged as a prognostic and predictive biomarker for detection of minimal residual disease (MRD), monitoring treatment response, and early detection of recurrence in cancer patients. In this study, we explored the utility of ctDNA-based MRD detection to predict recurrence in a real-world cohort of primarily early-stage non-small cell lung cancer (NSCLC) patients treated with curative intent. Methods: Longitudinal plasma samples were collected post curative-intent treatment from 36 patients with stage I-IV NSCLC. A personalized, tumor-informed assay was used to detect and quantify ctDNA in plasma samples. Results: Of the 24 patients with plasma samples available during the MRD window (within 6 months of curative surgery and before adjuvant therapy), ctDNA was detectable in two patients. Patients with ctDNA-positivity during the MRD window were 15 times more likely to recur compared to ctDNA-negative patients (HR: 15.0, 95% CI: 1.0-253.0, p = 0.010). At any time post-curative intent treatment, ctDNA-positivity was associated with significantly poorer recurrence-free survival compared to persistently ctDNA-negative patients (p < 0.0001). Conclusion: Our real-world data indicate that longitudinal, personalized, tumor-informed ctDNA monitoring is a valuable tool in patients with NSCLC receiving curative treatment to identify patients at high risk for recurrence.