Fernández MAB, et al. - In this prospective analysis, researchers investigated the utility of quantifying circulating tumor cells (CTCs) and CTCs/PDL1+ in patients treated with immunotherapy (IT) for non-small cell lung cancer. They isolated CTCs from peripheral blood samples as well as quantified CTCs. Using MACSQuantify and LASF Lite, data were analyzed. At treatment initiation and every 3 months and up to 12 months during IT, CTCs were determined, together with radiological evaluation in each extraction. Those patients who had no progression of the disease for at least 12 months were opted. Findings revealed that, a sustained response to long-term IT could be predicted by the absence of circulating CTCs/PDL1+. With regard to isolated CTCs without quantifying their associated expression of PDL1, no association with a particular pattern was evident, as well as no utility was seen in the detection of long survivors. WBCs that express PDL1 were found to be related to the appearance of relapse.