Association of High Level of Plasma Tissue Factor Activity with Venous Thromboembolism and Early Death in Lung Cancers.

8532 Background: Venous thromboembolism (VTE) is associated with tumor aggressiveness and mortality in cancers. Tissue Factor is the main activator of the coagulation but its variations in lung cancers (LC) have been less studied than D-dimers (DDi). We assessed plasma Tissue Factor Activity (TFa) and DDi and VTE events and mortality in patients with LC. Methods: This prospective study included patients, from 5 hospitals, recently diagnosed LC, without prior VTE or anticoagulant therapy within the last 2 months. Clinical and tumor data, Khorana score (KS), VTE events and overall survival (OS) were assessed (follow up 2 years). Blood samples were collected before any cancer treatment (V1): DDi (HemosIL) and TFa (chromogenic assay, Diagnostica Stago) were analyzed in a central lab. Independent nonparametric tests were used for group comparisons. A relevant clinical threshold of both markers was determined :1500 μg/ml for DDi and 1.2 ng/ml for TFa. Early death was compared using Cox model and Kaplan Meier curves and logrank tests. All tests were two-tailed tests and 0.05 was considered as significant. Results: Between 12/2014 and 01/2017, 302 consecutive patients (pts) were included (mean age 64 years, 61% males, 89% smokers, 85% NSCLC, 67% stage IV). At V1, TFa levels increased with cancer stage (p = 0.004) but not DDi. VTE incidence was 13,9%: 39 events (62% incidental and 51% pulmonary embolism) with 33 events within 6 months. KS failed to predict VTE (KS > 3 in 23% of the pts in VTE group vs 21% of the 302 pts, p = 0.42). DDi and TFa levels were not significantly different in VTE pts than in no VTE pts. But, a TFa > 1.2 ng/ml was significantly predictive in occurrence of VTE within the first 6 months (57.6% of the VTE pts vs 38.8% of no VTE pts, p = 0.04), and also within the first year (p = 0.03). Median OS was 17,6 months (m) in VTE pts and 19.5 m in no VTE pts (p = 0,97). Compared to survivors, higher levels of DDi and TFa were observed for the 38 pts who died within 6 months : 1.82 vs 0.67 μg/ml (p < 0.001) and 1.95 vs 0.33 ng/ml (p < 0.001) respectively. These differences were observed for the 97 pts who died during the first year, too. With thresholds of TFa > 1.2 ng/ml and DDi > 1500 μg/ml, median OS was significantly shorter: 14.4 m vs > 29.8 m ( p < 0,001) and 13.8 m vs 22.6 m (p < 0.001), respectively. Conclusions: High TFa level discriminates a population with high risk to VTE and early death in LC. This biomarker could take place in a predictive score. Clinical trial information: NCT02853188.