Analysis of Prethrombotic States in Patients with Malignant Tumors

Prethrombotic state, also known as prothrombosis state or high coagulation state refers to the dysfunction of hemostasis, coagulation, anticoagulation and fibrinolysis (Linkins et al., 2013). A previous study suggested that malignant tumor complicated by prethrombotic state is an underlying reason for thrombosis. Meanwhile, high coagulation state is associated with invasion and metastasis of malignancies (Rybicki et al., 2010; Koh et al., 2011). Lack of awareness of classical clinical features and specific reports of incidence, prethrombotic state still did not attract great attention of clinical medicine in preventing and managing high coagulation state. D-dimer (D-D) is a fibrin degradation product after fibrin monomers bound to activating factor and degraded by plasimin, which is a molecular biomarker for coagulation and fibrinolysis. High level of D-D reflects the double activation of coagulation and fibrinolysis system specifically by marking the formation of fibrin in blood vessels, which marks the high coagulation state and secondary increased fibrinolytic activity in vivo (Bigger et al., 1999; Jiang Z, et al., 2009). The current study aimed to investigate the incidence and related risk factors of prethrombotic state in patients with malignant tumors by detecting D-D.


Introduction
Prethrombotic state, also known as prothrombosis state or high coagulation state refers to the dysfunction of hemostasis, coagulation, anticoagulation and fibrinolysis (Linkins et al., 2013). A previous study suggested that malignant tumor complicated by prethrombotic state is an underlying reason for thrombosis. Meanwhile, high coagulation state is associated with invasion and metastasis of malignancies (Rybicki et al., 2010;Koh et al., 2011). Lack of awareness of classical clinical features and specific reports of incidence, prethrombotic state still did not attract great attention of clinical medicine in preventing and managing high coagulation state. D-dimer (D-D) is a fibrin degradation product after fibrin monomers bound to activating factor and degraded by plasimin, which is a molecular biomarker for coagulation and fibrinolysis. High level of D-D reflects the double activation of coagulation and fibrinolysis system specifically by marking the formation of fibrin in blood vessels, which marks the high coagulation state and secondary increased fibrinolytic activity in vivo (Bigger et al., 1999;Jiang Z, et al., 2009). The current study aimed to investigate the incidence and related risk factors of prethrombotic state in patients with malignant tumors by detecting D-D.

Methods
Following a fasting period of 8-10h, 3mL venous blood samples were extracted from the patients and into tubes containing 1/10 volume anticoagulant Sodium Citrate Solution (0.109mo/L). The samples were centrifuged at 3000*g for 10min. The plasma samples were then separated and maintained at -20℃ within 2h after blood samples collection. D-D levels were measured wityh the assistance of a Sysmex CA7000 automated blood coagulation analyzer and related reagents within 4h after blood samples collection.

Statistic analysis
Data analysis was performed using SPSS19.0 software. T-test was used on intra-group comparison and ANOVA analysis was performed for comparison between groups. P<0.05 was considered to indicate a statistically significance of difference.

Abnormal rate of D-D
Abnormality of D-D was found in 629 patients with a proportion of 43.29% (629/1453). Details were presented in Table2.

D-D and Gender
The abnormality of D-D was compared between male and female. Among 851 male, 370 samples (43.5%) showed abnormality and 259 in 602 (43.02%)female samples were abnormal, no statistically significant difference was detected between gender (x 2 =0.030, p>0.05).

D-D and Age
As shows in Table3, D-D abnormal rate increase with age gradually and the correlations among groups are distinct (F=2.224, p=0.038).

Discussion
Prethrombotic state, also known as prothrombosis state or high coagulation state, is a pathological state, manifesting high blood coagulation to form thromboembolism easily because of hyperfunction of hematischesis and antithrombotic (He et al., 2009). Migrating phlebitis in patients with cancer was first reported by Aramnd Trousseau in 1865, and was claimed that spontaneous clotting tendency occurred without the existence of inflammatory response, which could be called 'Trousseau Syndrome'. Studies have shown that tumor cells could undermine the balance of coagulation, anticoagulant and fibrinolytic system through multiple mechanisms, which leads to prethrombotic state. Tumor cells is reported to induce inflammatory response, release cytokine, injury vascular wall directly or indirectly by releasing tissue factor (TF) with procoagulation activity, e.g., cancer procoagulation (CP), plasminogen activator inhibitor-1 (PAI-1), human fibrinogen-like protein 2 (hfgl2), which could activate coagulation of patient and cause coagulation dysfunction. In addition, operations, radiotherapy and chemotherapy, hormone therapy, drainage-tube and some medications may also bring about high coagulation state.
The incidence rate of malignant tumor complicated by prethrombotic state is not clear. López suggested that about 50% cancer patients displayed laboratory indicators anomalies of coagulation system (López JA et al., 2009). According to Spyropoulos et al, 90% malignant tumor patients with metastasis presented abnormal coagulation state, 4%~30% patients had deep venous thrombosis (DVT) within 6~12 months of cancer diagnosis, 10%~25% patients were diagnosed malignant tumor within 3~5 yeas of idiopathic DVT and more than 75% among them were confirmed within 1 year.
Prethrombotic state exists in many diseases (Ouyang et al., 1999;Chen et al., 2012;2014;Huang et al., 2012;Wang et al., 2012;Tan et al., 2014). The tumor types in our data covered all kinds of common solid tumors. Of all 1453 patients, 629 revealed plasma d-dimer abnormality (43.29%). Subgroup analysis based on gender showed that D-D abnormal rate for male patients was 43.5%, and for female was 43.02%, which implied that there is no statistically significant difference between gender. However, D-D abnormal rate increase with age increase, which was validated with Zeng's report (Zeng et al., 2012;Isaia, 2011). Several possible reasons are as follows. coagulation and fibrinolytic system was relatively stable in younger than in elderly patients. Incidence of chronic diseases increased and chronic hypoxia, inflammation, vascular degenerative change complicated by tumor with advancing age (Sud et al., 2009;Douma RA et al., 2010;Jaffrelot et al., 2012;Wei et al., 2012).
Our current study indicated that the incidence of prethrombotic state varied with tumor stage. The incidence rate of prethrombotic state raised with the the increasing stage of tumor and our data showed that D-D abnormal rate in phaseⅠis 2.0%, 6.2% in phaseⅡ, 47.6% in phaseⅢ and up to 83.1% in phaseⅣwith significant differences. Thus, advanced tumors are risk factors for prethrombotic state and patients of terminal malignant tumors are more susceptible to have prethrombotic state. (López et al., 2009;Sud et al., 2009) It is generally known that prethrombotic state is closely related to thrombotic events and the incidence is as high as 4%~20%, which is the second leading cause of death of malignant tumor patients. Yan and others summarized clinical manifestations, risk factors and treatment of 40 patients with high coagulation state or thrombosis so as to find that the starting-time of thrombosis of 77.5% patients was in 2 months after high coagulation state happened. Analysis of clinic data of 20 cases of malignant tumor complicated by DVT pointed out that the total media survival time was 6.3months, the media survival time of patients whose D-D levels were twice above normal was 4.5 months and twice below normal was 7.3 months. Therefore, early diagnose and intervention of malignant tumor complicated by prethrombotic state to prevent thrombosis should be taken in clinical practice as DVT negatively impact on life quality and threaten the lives of cancer patients.
As the number of tumor patients steadily grow, it's important to judge prethrombotic state early. Partially, that has to do with thrombosis events, prethrombotic state has a close ties to metastasis on the flip side. Prethrombotic state is not only the pathological manifestation that tumor leads to, but also the key factor of tumor etiology and independent risk factor for prognosis of tumor. By the clinical study of Hu et al. on blood coagulation state of 180 malignant tumor patients, D-D level of tumor inchoate group and locally advanced tumor group had significant difference compare with the metastasis group. The D-D indicator in inchoate group, locally advanced tumor group and metastasis group shown a gradual increasing trend, which signified that the contents of plasma d-dimer associated with tumor staging. These illustrates that, on the one hand, prethrombotic state is involved in the process of tumor invasion and metastasis, which means tumor cells are aggressive. Tumor cells produce thrombotic accelerator specifically, which directly or indirectly activate coagulation process through inducing inflammatory response which feeds back onto tumor cells and leads to thrombotic accelerator releasing. Malignant cells settle into the vascular with the adhesive attraction of microthrombus to escape from immune system attack and go into perivascular tissues, which facilitate invasion and metastasis. On the other hand, prethrombotic state is strongly relevant to progression which includes tumor staging, angiogenesis formation and metastasis as well as adhesion, spreading, movement, proliferation and differentiation of cells (Farge et al., 2010).
This study demonstrated that the incidence of prethrombotic state was variable in different types of tumor and the D-D levels of patients elevated by degrees which indicated that blood coagulative and fibrinolytic activity strengthened with the increasing of tumor staging and tumor burden thus trapped body in a vicious circle, which resulted thrombosis and tumor progression ultimately. After comparative analysis between the plasma D-D level of 0~4 weeks and 4~8 weeks before the end of 72 malignant patients who were impending death, zhang et al. found that the D-D level of 0~4 weeks significantly higher than 4~8 weeks before their last days (P=0.002). , which suggested that plasma D-D level showed increasing direction following disease progression in terminal phase of malignancies, form which they concluded that malignant progression in connection with the activation of coagulative and fibrinolytic system.
As a consequence, prethrombotic state predicts the invasion, metastasis and other malignant biological behavior indirectly. The increasing degree of it may often provide the clue of disease progression and poor prognosis. Detecting prethrombotic state promptly and primary or secondary prophylactic anticoagulation therapy specifically could reduce thrombotic events, improve quality of life and prolong survival period. Meanwhile, there are certain practical signification for anti-metastasis and improving clinical effects of anti-tumor.
Currently, several international large scale clinical trials support the validity of anticoagulation therapy. It has been shown by the MEDENOX trail that anticoagulation therapy significantly reduced the risk of DVT (Relative Risk=0.37 (p<0.001). In the meantime, PREVENT trail saw the obvious drop of incidence of DVT in anticoagulation therapy group compared with placebo group. 2.77%:4.96%, p=0.0015, Relative Risk reduced45% (ARR=2.19). In ARTEMIS trail, the incidence rate of DVT in medicine group and control group were 5.6% and 10.5% respectively. OR=49.5% (p=0.029). These 3 clinical trails consisted of 5000 cases in total. Although these data only contained 5%~15% malignant patients to allow us to discuss more concrete data, prophylatic anticoagulant therapy significantly reduced the incidence and risk of DVT, from the trails results.
A clinical trail aimed at patients with solid tumor during advanced stage who ruled out thrombosis was implemented in 2004, which randomly divided 385 cases into Low molecular weight heparin group (LMWH) and placebo group, 2 groups. After 12-week-treatment, 2 and 3-year survival rate of patients with LMWH treatment was remarkable than that in the placebo group (78% :55%60%:36%, p=0.03). In a separate study, 302 solid tumor patients without thrombosis were treated with therapeutic dose of LMWH for 2-week and half-quantity of LMWH for 4-week as maintenance therapy. Clinical follow up of these cases revealed that mortality of 12-month and 24-month were 12% and 10% respectively, while overall survival prolonged from 6.6 months to 8 months. With regard of median survival, comparing with 9.4 years of placebo group, it was 15.4 years in LMWH group (Kakkar et al., 2004). So, NCCN and ASCO recommend anticoagulant therapy for cancer hospitalized patients without contraindication.
We conclude that the prethrombotic state of malignant patients closely related to their prognosis and basic life quality because the rising plasma D-D level correlates with tumor invasion, progression and poor prognosis. Therefore, growing recommend of D-D quantitative measurement as indicator to evaluate prethrombotic state and prognosis of malignant patients. Pay close attention on the change of prethrombotic state of malignant patients to detect thrombosis as early as possible, which is of great importance to improve life quality and prognosis of advanced malignant patients.
In conclusion, the activation of coagulation is associated with tumor growth, angiogenesis and metastasis. In turn, tumor further stimulate the activation of the coagulation process. In its incubation period, malignant tumor may cause hypercoagulable state or share some common mechanism with thrombosis. If this assumption is correct, anticoagulant drugs can interfere not only malignant transformation of cells, but also tumor development (Bobek V, 2012). In clinical practice, discovering the prethrombotic state complicated by malignant tumor and giving anticoagulation therapy in time which could improve blood hypercoagulable, reduce thrombotic events, improve the quality of life and prolong survival time of patients and prevent tumor invasion and metastasis may have important implications. This may be another vital aspect of treating tumors (Ma et al., 2007;Imberti et al., 2009).