Droplet Biosciences and academic collaborators published a study in Clinical Cancer Research validating postoperative lymph drain fluid as a sample for circulating tumor DNA (ctDNA) detection of molecular residual disease (MRD) in HPV‑independent head and neck cancers. The team compared lymph fluid to time‑matched plasma collected 24 hours after surgery and found substantially higher sensitivity for lymph fluid in predicting recurrence. In the initial cohort, lymph fluid MRD detection showed 76% sensitivity and 63% specificity, with replication cohort results of 65% sensitivity and 70% specificity. Matched plasma at the same early postoperative timepoint was far less predictive (35% sensitivity). The investigators highlighted lymph fluid’s superior performance for locoregional relapse, which accounts for the majority of recurrences in this population. Droplet’s CSO noted the test could stratify intermediate‑risk patients where decisions about adjuvant radiotherapy and chemotherapy are currently empirical, setting up further clinical validation and potential utility in post‑surgical decision making.