Factor IXi-antithrombin (IXiAT) and thrombin-antithrombin (TAT) complexes in lung cancer patients

Impact of the fibrinolytic enzyme system on prognosis and survival associated with non-small cell lung carcinoma

Comprehensive studies of fibrinolysis in non-small cell lung carcinoma have been limited, and assignment of patients to high/low prognosis groups based on arbitrary cut-offs utilizing fibrinolytic measurements is unstandardized. This study was performed in 166 patients to examine the effects of cut-off values determined in three ways. Model 1 assigned patients to one of three equal groups (low, medium, high) based on fibrinolytic measurements made at diagnosis, Model 2 divided patients into low/high groups using median values, and Model 3 grouped according to the parameter being above/below normal range. In model 1, raised plasma fibrinogen, D-dimer and soluble fibrin were positively associated with poorer survival. In model 2, tissue plasminogen activator antigen was additionally related to poorer prognosis. Model 3 identified seven parameters as significantly related to survival, two not identified by the other models becoming significant [plasmin-antiplasmin, tissue plasminogen activator inhibitor-1 (PAI-1) antigen]. Using multivariate analysis, plasma fibrinogen level was the most uniformly significant parameter. Relative risk estimates indicated that raised plasma fibrinogen, soluble fibrin and D-dimer were associated with increased risk of death. Use of the normal/above normal cut-off is recommended to provide the maximum number of significant parameters relating to prognosis, and increased plasma D-dimer, PAI-1 antigen and fibrinogen were most closely related to survival/prognosis.

Prognostic impact of an activation of coagulation in lung cancer

BACKGROUND

There is evidence that activation of coagulation by influencing tumour biology may have impact on clinical course of lung cancer.

PATIENTS AND METHODS

We measured the activation markers thrombin-antithrombin complex (TAT) and prothrombin fragment F1 + 2 in 99 lung cancer patients immediately after diagnosis, before antineoplastic treatment. Outcome was assessed at the end of appropriate standard primary therapy (four to six courses of chemotherapy, surgery or radiation).

RESULTS AND CONCLUSIONS

The activation markers (means +/- SEM) were lower in the 33 responders (RSP; complete or partial remission) than in the 66 non-responders (NRSP): TAT 3.96 +/- 0.48 vs. 9.69 +/- 1.57 micrograms/l (P < 0.001), and F1 + 2 1.09 +/- 0.09 vs. 1.64 +/- 0.25 nmol/l (P < 0.05). TAT levels were > 6 micrograms/l in 30 of 66 (45%) NRSP, but only 4 of 33 (12%) RSP. 88% of patients with TAT < or = 6 micrograms/l achieved remission, and 45% with TAT > 6 micrograms/l (P = 0.0014). In the subgroup of 46 patients with advanced disease, the six RSP showed lower TAT than the 40 NRSP: 4.65 +/- 0.94 vs. 11.92 +/- 2.49 micrograms/l (P < 0.01); one of six (17%) RSP, but 21 of 40 (53%) NRSP showed TAT > 6 micrograms/l. These data suggest that in lung cancer the activation of coagulation is an independent prognostic factor, since TAT levels were different between RSP and NRSP, also within the homogeneously unfavourable metastatic subgroup. It should be further studied, whether TAT can identify patients, whose prognosis could be improved by anticoagulation as an adjunct to standard antineoplastic therapy.

Cancer and venous thromboembolism

Neoplastic cells can activate the clotting system directly, thereby generating thrombin, or indirectly, by stimulating mononuclear cells to synthesize and express various procoagulants. Clinical manifestations of increased thrombin generation may be accentuated by down-regulation of endothelial cell counterregulatory mechanisms, such as decreased hepatic synthesis of antithrombin III and protein C. Cancer cells and chemotherapeutic agents can injure endothelial cells, thereby intensifying hypercoagulability. In addition, normal endothelial cell function. may be disrupted by various defects in platelet function. Currently, primary prevention of venous thrombosis should be considered for cancer patients (1) during and immediately after chemotherapy, (2) when long-term indwelling central venous catheters are placed; or (3) when hospitalization for cancer is characterized by prolonged immobilization, trauma, or surgery. Secondary prevention of recurrent venous thrombosis usually necessitates anticoagulation. In some patients with cancer, the condition is resistant to warfarin, and long-term adjusted high-dose heparin is required. For patients unable to tolerate heparin or warfarin because of major bleeding problems, placement of an inferior vena caval filter should be considered. The diagnosis of venous thrombosis may help to uncover previously occult carcinoma by prompting a complete physical examination, chest roentgenography, and mammography. However, extensive cancer screening with total-body computed tomography or magnetic resonance imaging has not been shown to be cost effective for patients with venous thrombosis.

Impaires Anticoagulant Activity of Protein C and Activation of Neutrophils in Extensive Lung Cancer

Lung cancer is associated with an increased incidence of thrombosis. An activation of coagulation is demonstrable in lung cancer patients by sensitive activation markers, as well as a stimulation of neutrophil granulocytes, which are known to interfere with hemostasis, e.g., by degrading inhibitory proteins. We assessed antigen level, amidolytic activity, and clotting activity of the plasma anticoagulant protein C and the activation markers thrombin-antithrobin complex (TAT) and neutrophil elastase-α1-antitrypsin complex (EAT) in 67 lung cancer patients before antineoplastic treatment was begun. The protein C clotting activity was lower (p = 0.010) in the patients with extensive than in those with limited disease. However, the median levels remained within the normal range in both groups (91 vs. 108% of normal). The median amidolytic activity levels (110 vs. 117% of normal ; NS) were higher than the protein C antigen levels (82 vs. 77% of normal; NS) in- both groups. There was no significant correlation of protein C measurements with TAT levels, but there were significant negative correlations between EAT and protein C clotting activity and antigen level. The data suggest that in patients with lung cancer, there may be an alteration of the protein C molecule, which reduces antigen level and impairs clotting activity without affecting amidolytic activity. The negative correlation with EAT levels might point to limited degradation of protein C by neutrophil enzymes, leading to partial loss of epitopes detected by the immunologic determination and of structures necessary for the biologic effect of protein C upon clotting time. Further studies should clarify whether such a modification of protein C could contribute to the increased incidence of thrombosis in lung cancer patients. Key Words: Lung cancer-Neutrophil elastase-Protein C.