The prognosis of head and neck squamous cell carcinoma (HNSCC) is largely based on disease stage. Despite improvements in treatment, recurrence rates are still considered high. Currently, disease progression or regression after curative treatment is monitored by clinical evaluation combined with flexible endoscopy and/or imaging. However, specificity of imaging is low due to the posttreatment effects. Detection of circulating tumor DNA (ctDNA) from blood samples of HNSCC patients is a minimally invasive technique that could lead to an earlier detection of recurrence. In addition, digital droplet PCR (ddPCR) could be used to sensitively detect these mutational targets. Future study on ctDNA using ddPCR in blood samples of HNSCC patients is recommended during the follow-up stage to detect recurrences in a timely manner.

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