8017 Background: Circulating tumor DNA (ctDNA) is a promising biomarker for detecting molecular residual disease (MRD) and predicting recurrence after curative treatment in non-small cell lung cancer (NSCLC). Ultrasensitive personalized assays have demonstrated clinical validity at detection thresholds of ~80-100 parts per million (PPM). As this assay can detect ctDNA at concentrations an order of magnitude lower (below 10 PPM), we extend these analyses to explore the clinical outcomes of patien