Longitudinal analyses of microparticle-associated tissue factor activity and venous thromboembolism (VTE) in cancer patients

E.-M. Reitter, A. Kaider, C. Ay, J. Thaler, C. Marosi, I. Pabinger (Vienna, Austria)

Acquired problems and alterations of coagulation
Date: 17.02.2017,
Time: 17:15 - 18:15

Objective: Tissue factor (TF)-bearing microparticles (MP) are discussed to have an impact on VTE occurrence, specifically in pancreatic cancer patients. Therefore, we evaluated changes in this parameter longitudinally to see whether longitudinal determination of TF-MP could lead to an improvement of VTE prediction in cancer patients.

Methods: Of 112 cancer patients (with pancreatic, colorectal, lung cancer or glioblastoma), who were included before receiving chemo- and/or radiotherapy and then followed during the course of disease over a period of six months, 11 developed VTE. We investigated these 11 patients (five with pancreatic cancer and three each with glioblastoma and lung cancer), as well as 27 patients (ten with pancreatic, five with colorectal and six each with lung cancer and glioblastoma), who did not develop VTE and who served as control group. Of these 38 patients (19 female, 19 male) with a mean age of 60.7 years (± 8.9), venous blood samples for determination of TF-MP activity were drawn on a monthly basis over six months. The measurement of TF-MP activity was performed according to standardized protocols for a chromogenic kinetic assay. Study end points were VTE occurrence, death or completion of the study period (max. 250 days).

Results: TF-MP levels did not differ between patients with VTE (n=11) and those without VTE (n=27). The median baseline value was 0.08 pg/ml for both, patients with VTE [interquartile range (IQR) 0.03-0.29], and those without VTE (IQR 0.00-0.46), within the study period. After two months of follow-up, a median value of 0.08 pg/ml (IQR 0.07-0.13) in VTE patients and a median value of 0.07 pg/ml (IQR 0.0-0.15) in those without VTE were found. Three months after inclusion, the median value for patients with VTE was 0.22 pg/ml (IQR 0.14-0.90) and 0.04 pg/ml (IQR 0.00-0.42) for those without VTE. At the last sampling, a median value of 0.13 pg/ml (IQR 0.13-0.13) for the one patient, who developed VTE thereafter, and a median value of 0.06 pg/ml [IQR 0.00-0.38] for patients without VTE, was observed. No statistically significant prognostic influence of the TF-MP levels on VTE occurrence was observed, neither at baseline (p=0.824), nor at the six monthly sampling time points (p=0.346) accounting for longitudinal measurement.

Conclusion: We conclude that TF-MP activity does not allow prediction of VTE occurrence in cancer patients.