The prognostic role of circulating tumor cells in lung cancer.

INTRODUCTION: Circulating tumor cells (CTCs) can be isolated from the peripheral blood of cancer patients. Several studies to assess the prognostic and/or predictive role of CTCs have been performed in lung cancer patients. AREAS COVERED: The state-of-the-art of the role of CTCs in lung cancer patients is reviewed and discussed. A structured search of bibliographic databases for peer-reviewed research literature and of main meetings using a focused review question was undertaken. Expert commentary: Although in the revised studies different technologies, cutoffs, patients' populations and statistical approaches have been used, a high CTCs count as prognostic role in small-cell lung cancer is suggested, whereas additional studies are required to confirm this correlation in non-small-cell lung cancer. A reduction in CTCs count is also likely to be correlated with the lung cancer patients' outcome. Large prospective trials need to confirm the prognostic and/or predictive role of CTCs in lung cancer.