Egyud M, et al. - Blood samples from 8 candidates were analyzed to explore circulating tumor DNA to detect the recurrence in head and neck cancer. They recognized mutations in plasma circulating tumor DNA from pre-treatment blood samples and longitudinally during standard follow-up. They confirmed tumor mutations in 7 patients whereas baseline circulating tumor DNA was positive in 6 individuals. They noted recurrence in 4 cases, 2 of whom had detectable circulating tumor DNA earlier to recurrence.