Wang HM, et al. - Using a negative selection strategy and flow cytometry protocol, circulating tumor cells (CTCs) were detected to assess the part played by baseline CTCs before and during concurrent chemoradiotherapy and also to ascertain the influence of CTCs on outcomes in patients with head and neck squamous cell carcinoma. Baseline CTCs were significantly associated with staging. In 47 concurrent chemoradiotherapy responders, CTC counts were significantly decreased within 2-4 weeks. They reported an association of change of CTC counts with progression-free survival (PFS) and overall survival (OS). A longer PFS and OS was indicated by a decrease of CTC within the first month indicates, signifying that CTC dynamics could be more important than CTC number.