In vivo isolation of circulating tumor cells in prostate cancer patients by a medical device.

Abstract

e22055 Background: CTCs are discussed as a prognostic and stratification biomarker, and may help to assess the treatment efficacy. The aim was to demonstrate proof of concept of in vivo CTC isolation in Prostate cancer patients (PCa). Methods: A medical device (CellCollector) was inserted in a cubital vein for 30 minutes. The interaction of target CTCs with the CellCollector was mediated by antibodies to the epithelial cell adhesion molecule (EpCAM). To confirm binding of CTCs to the wire, immunohistochemical staining against Cytokeratin and CD45 was performed. There were 226 applications of the device in 16 metastasized PCa (PCa-m) with up to 8 wire applications per patient, 24 localized PCa (PCa-l) with up to 3 wire applications per patient as well as 19 men with benign prostate hypertrophy (BPH) and 21 women as control group with only one wire application. CTC counts from 22 PCa patients with 58 applications were directly compared to the CellSearch technology. Results: We obtained in vivo isolation of CTCs in 73 of 98 applications to PCa patients (74.5 %). The sensitivity for metastasized PCa was (86.2%) and for local PCa (57.5%), respectively. Follow up data of one patient with PCa-m: 2009 diagnosed PCa with multiple metastases. 2 years later PSA of 11.2ng/mL and 25 CTCs. After transurethral resection and removal of a brain metastasis, CTCs decreased to 20 cells with no effect on PSA levels. 4 months later we observed 187 CTCs and a PSA level of 76ng/mL, which was correlated with the patient condition. In PCa-l patients we observed prior radical prostatectomy (n=18) and 6 (n=15) and 12 (n=7) months after surgery CTC numbers on average of 18.2, 2.8 and 1.4, respectively. In the direct comparison of the CellCollector and CellSearch we showed detection rates of 65% (13/20) and 20% (4/20). Conclusions: We demonstrate the use of CTCs besides PSA during therapy adjustment in PCa patients In summary the CTC detection rate of the CellCollector in PCa-m and PCa-l in comparison to the CellSearch method increased by 26% and 45%. Further molecular genetic CTC characterization as well as multiple antibody coating at the CellCollector will assume crucial information for therapy decisions. Clinical trial information: ISRCTN10403616.