Abstract 5584: Circulating tumor cells in the peripheral blood and leukapheresis product of non-small cell lung cancer patients

Abstract

Abstract Introduction The number of circulating tumor cells (CTC) isolated by the FDA approved CellSearch (CS) system in 7.5 mL of blood of metastatic and non-metastatic non-small cell lung cancer (NSCLC) patients is low or absent. Processing a larger blood volume could yield a greater amount of CTC from these patients. An approach to probe larger volumes is using diagnostic leukapheresis (DLA) where the blood can be split into its components after which selective harvesting of mononuclear cells (MNC) including CTC can take place. Methods Patients with histologically proven NSCLC who either have been recently diagnosed or are eligible for new therapy can participate in this ongoing study. Patients had DLA for MNC collection derived from one total body blood volume. Before and after DLA, whole blood was drawn in a CellSave blood collection tube and analyzed by CS. The obtained DLA product was divided for analysis. 2x108 cells (on average 2mL of DLA product, representing ~100mL of blood) was diluted in 7.5 mL buffer, and analyzed by CS. 9 mL of the DLA product (on average 1x109 cells) was fixed and depleted of leukocytes using the RosetteSep CD45 depletion kit (Stemcell Technologies), allowing processing of a larger volume, followed by CS analysis. Results of molecular characterization of the detected CTC is pending. Results So far, a total of 8 DLA's were performed in 7 stage 4 NSCLC patients. Sample collection took place before (t=0) and/or after (t=1) treatment. Patients underwent DLA in about 110 minutes, at this time an average of 4860 mL of blood was processed. No complications occurred, no post-procedure complaints were recorded. Similar DLA products with an average of 95 mL were obtained. CTC counts for these patient samples are shown in the table below. CTC counts blood and DLAPatientt=#CTC pre blood#CTC post blood#CTC DLA (~2mL, 200x106 cells)#CTC depleted DLA (~9mL, 900x106 cells)101n/a114113020203514602031000040n/a04495000166000029020114 Conclusion DLA is a novel method to collect CTC from the blood. DLA can result in the detection of CTC where the use of 7.5mL of blood is not sufficient. Additionally, DLA shows an increase of CTC yield in patients with CTC detected in 7.5 mL of blood. Citation Format: Kiki C. Andree, Menno Tamminga, Anouk Mentink, T Jeroen Hilterman, Harry J. Groen, Leon W. Terstappen. Circulating tumor cells in the peripheral blood and leukapheresis product of non-small cell lung cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5584.