Early real-world experience monitoring circulating tumor DNA in resected early-stage non–small cell lung cancer

Objective To evaluate the impact of monitoring circulating tumor DNA (ctDNA) on the detection and management of recurrence in patients with resected early-stage, non-small cell lung cancer (NSCLC). Methods Between October 2021 and March 2023, post-operative ctDNA was monitored in NSCLC patients (N=108). Longitudinal blood samples (n=378 samples) were collected for prospective ctDNA analysis at 3-month intervals, post curative-intent resection. A tumor-informed assay was used for the detection and quantification of ctDNA. The primary outcome measure was a ctDNA-positive result. The secondary outcome measure was changes in practice after a ctDNA-positive result. Results The mean age of the patients in this cohort was 68.1 years. Of the 108 patients, 12 (11.1%) patients were ctDNA-positive at least at one timepoint post surgery, of which 8 (66.7%) had clinically evident recurrence and the remaining 4 had limited clinical follow-up. Of the 10 patients with recurrent disease, 8 demonstrated ctDNA-positivity and 2 patients with brain-only metastases. Post-operative clinical care was altered in 100% (12/12) of ctDNA-positive patients with 58.3% (7/12) receiving an early CT scan and 100% (12/12) receiving an early PET-CT scan as part of their surveillance strategy. Amongst the patients who received an early PET scan, 66.6% (8/12) were positive for malignant features. Conclusion Routine monitoring of tumor-informed ctDNA after curative intent therapy improved patient risk stratification and prognostication.