Correlation of coagulation parameters with prognosis of carcinoma breast patients

Plasma fibrinogen level as a risk factor for the long-term survival

Fibrinogen, which is a 340-kDa glycoprotein in plasma, consists of three pairs of polypeptide chains designated as Aα, Bβ, and γ. A continuous extravasation of fibrinogen occurs when cancer cells secrete vascular endothelial growth factor. Fibrinogen usually increases in response to any physiologic stimulation either in the form of inflammation, tissue injury, or malignancy. According to various studies, pre-surgical plasma fibrinogen was discovered to be an independent risk factor in postmenopausal breast cancer patients following surgical treatment that influences overall survival, disease-free survival, and distant metastasis-free survival. Significant variation in plasma fibrinogen levels among females has been observed before and after menopause, so it is essential to investigate menopausal breast cancer patients as a separate entity.^[24] Fibrinogen gets transformed into fibrin after cleavage by thrombin which is crucial in stabilizing blood clots and facilitate hemostasis mechanism.^[25] Fibrinogen as well as fibrin is a significant factor in host defense mechanisms, inflammatory response, wound healing process, cell-matrix interactions, tumor formation, tumor growth, and metastasis.^[26] In breast cancer tissue, fibrinogen is found in abundance when compared with non-cancerous tissues.^[27] The changes in fibrinogen level during neoadjuvant chemotherapy are validated by various researches. Hence, plasma fibrinogen level is found to be a vital coagulation biomarker for postoperative metastasis and mortality in advanced-stage breast cancer patients, especially who received neoadjuvant chemotherapy. Thus for post operative follow up,the plasma fibrinogen level could be a simple,cost effective and valuable predictive indicator.

Platelets: Thrombocytosis and its association with cancer

The role of platelets and thrombocytosis in facilitating tumor growth and metastasis was very first suggested by Gasic et al.^[28] Platelets have the property of invading the tumor microenvironment as well as interacting directly with cancer cells. Its role has been also established in protecting circulatory tumor cells from the deleterious attack of the immune system. It also protects the circulatory tumor cells (CTCs) from the lethal effects of other pro- apoptotic stimulants. These tumor cells in circulation are used to get attached to the endothelium and provide signals for the establishment of a premetastatic niche. Thus, in the pathophysiology of cancer, a vital role is played by platelets. In malignancy, receptor-mediated mechanisms directly activate the platelets though these can also be activated with the release of platelet-activating molecules through an indirect pathway. Platelets release the cytokines and growth factors which support a microenvironment of proliferation and angiogenesis. Thus, platelets have been noticed playing a very important role in the promotion of pro-tumoral mechanisms. Thus, platelets also assist metastasis through supporting evasion of the immune system by circulatory tumor cells.

In malignancy, platelets have an impact on the potential effects of chemotherapy and other targeted therapies. Hence, an effective strategy to target platelet-tumor cell interactions without hampering normal platelet functions is a promised field so that life-threatening complications can be avoided. Many studies have concluded an inverse correlation between thrombocytosis and disease specific survival (DSS) in different types of malignancy, e.g., in lung carcinoma, colon cancer, breast cancer, pancreatic cancer, renal carcinoma, and glioblastoma.^[14] Platelets to lymphocytes ratio can be used as a diagnostic and predictive marker in cancer patients. Platelets have the ability to promote tumor angiogenesis, facilitating rapid tumor growth. Platelets also maintain the tumor vascular integrity affecting tumor metastasis. it also facilitate epithelial mesenchymal transition and support tumor cells in evasion of phagocytosis of host immune system cells. If the platelet-based biomarkers are included in evolving “liquid biopsy” strategies, it could improve the diagnostic accuracy in cancer patients and have potential for treatment response prediction.

PT and aPTT and their prognostic implications

The extended aPTT is usually noticed in newly diagnosed carcinoma breast patients. It is likely accredited to DIC, marked by extensive activation of the clotting cascade, formation of microthrombi, and consumption of clotting factors. This may present either with excessive clotting or bleeding tendencies. The primary mechanism of thrombosis formation involves the shedding of microparticles containing phosphatidylserine by circulating tumor cells, which provides a negatively charged surface supporting the assembly of coagulation complexes. A cancer procoagulant, cysteine protease generated by cancer cells, triggers direct activation of factor X.^[29] In breast cancer, liver function can directly be affected through metastasis. So reducing the clotting factors synthesis, which leads to factor deficiencies, thus prolongs aPTT. Furthermore, some breast cancer patients may develop antiphospholipid antibodies, which include lupus anticoagulant and thus can also cause prolonged aPTT.^[30] A prolonged aPTT can signal an increased risk of bleeding or the presence of coagulopathy, liver dysfunction, or thrombotic disorders, so it is mandatory to do careful assessment to rule out or manage these conditions in breast cancer patients.

D-dimer and its association with disease progression

D-Dimer is a product of plasmin-mediated fibrin degradation. Its high values reflect systemic coagulation and fibrinolytic activity. It is frequently used in the diagnosis of VTE. High values of D-dimer are widely evaluated in various carcinomas including breast cancer for survival prediction and treatment response assessment.

D-dimer level is a clinically important marker for progression so indicates toward a relation between hemostasis and tumor progression. A strong interaction between angiogenesis and homeostasis in breast cancer has also been established in various studies.^[31]

Multiple tumor-host interactions occur in the metastasis process. After leaving the primary tumor, these metastatic cancer cells in circulation drift into the lymphovascular system and set up a new blood supply at their metastatic site. Fibrin remodeling is almost certainly involved in all steps of metastasis and has been proven to play a crucial role in new vessel genesis.^[32] Various studies showed upregulated fibrinolytic activity in the form of higher levels of plasma D-dimer in malignant disease.

Predictive models and biomarkers for survival in breast cancer

There are various emerging genomic assays, which furnish a molecular portrait of the tumor, that help to predict recurrence risks and can help in decision making for adjuvant therapy so that more personalized and précised treatment can be delivered to the patient. The most common assays are Oncotype DX and MammaPrint. Predictive models are rapidly evolving in terms of sophistication, incorporating diverse data sources such as genetic, molecular, and clinical variables to predict outcomes and to tailor therapeutic strategies. These models tend to use more advanced statistical methods and polished machine learning techniques to forecast disease progression and individualized specific survival with high accuracy. The integration of these predictive tools into clinical implications holds the promise of more précised, individualized, and tailored treatment plans that improve overall patient outcomes.^[33]

The first large prospective study, “The HYPERCAN,” was specifically designed to assess hemostatic activation and its association with recurrence risk in breast carcinoma patients. It characterized the baseline hypercoagulability status before starting systemic chemotherapy and investigated the capacity of plasma thrombotic biomarkers to predict recurrence. As regards thrombotic biomarkers, patients who subsequently experienced distant recurrence showed significantly (P < 0.05) higher circulating levels of F1+2, compared to disease-free subjects. This study concluded that hypercoagulable state is often associated with poor disease prognosis in cancer patients. Thrombin generation (TG) may be useful to identify patients at high risk of cancer recurrence and is significantly increased in operated breast cancer patients who relapse within 2 years. TG contributes to stratify patients at different risks of relapse during chemotherapy.^[34]

In cancer patients, the risk of thromboembolism and systemic hypercoagulability has been well documented and the concept of bidirectional pathways between cancer and the blood coagulation system has been accepted.

The thrombophilic condition in breast cancer involves different highly interconnected mechanisms. TF, the main trigger of blood coagulation, plays a crucial role. In a pivotal study, performed in surgical specimens of human breast carcinomas, it was found that all tumor tissue extracts expressed functional procoagulant activities, including TF-like activity.^[35] Specific genetic alterations in malignant cells were linked to TF overexpression. The prothrombotic effect is further enhanced locally by the expression of TF on tumoral stroma and vascular endothelial cells and systemically by the release of TF- bearing extracellular vesicles.

Cancer-associated hypercoagulability is further influenced by a tight biological link between cancer, inflammation, and the hemostatic system. Cancer-induced local and systemic inflammatory mechanisms activate hemostasis through pro-inflammatory cytokines and neutrophil extracellular traps. The close bidirectional crosstalk between cancer and the hemostatic system promotes hypercoagulability in cancer patients. Consequently, different degrees of systemic hemostatic activation can reflect the underlying biology of tumors. Thus, markers of systemic hypercoagulability and hemostatic activation might be suitable candidates as surrogate parameters for the clinical aggressiveness of cancers.

Routine thromboprophylaxis is usually not recommended in breast cancer patients but individualized risk assessment should be encouraged. The incorporation of hypercoagulability biomarkers could increase the sensitivity of risk assessment models (RAM) to identify patients at VTE risk. The identification of breast cancer patients at risk of VTE and the optimization of thromboprophylaxis is a challenging task because VTE risk varies according to the cancer type and its site. It is potentially influenced by its evolution, the histology and the localization of the cancer, the duration and the intensity of chemotherapy or other adjuvant treatments. The development of RAM for VTE risk stratification adapted for cancer patients and their prospective clinical validation is utmost required. Such a RAM – focused on cancer patients receiving chemotherapy – has been proposed and prospectively validated by Khorana et al.^[36] This model includes some clinical risk factors such as the site of cancer, the body mass index, and the increased pre-chemotherapy platelet and leukocyte counts. However, other variables related to the malignant disease which contribute to the VTE risk (i.e., the stage and the type of anticancer therapy) are lacking. The levels and the procoagulant activity of plasma derived medicinal products (Pd-MP) are interconnected with the biological activity and the overall burden of cancer. TG reflects the procoagulant properties of both breast cancer and chemotherapy in the initial period of cancer diagnosis. Thus, the weighted incorporation of the biomarkers of cellular and plasma hypercoagulability in RAM for VTE might improve their predictive value.

Furthermore, to improve the individual prediction recurrence in high-risk populations, combining clotting biomarkers with previously established breast cancer prognostic factors can be a good assessment tool.

The occurrence of VTE in patients with metastatic breast cancer upon commencing anticancer treatment significantly affects disease burden, quality of life, and healthcare expenditure. Consequently, it is essential to accurately discern patients with a significant risk of developing thrombosis, thereby warranting thromboprophylaxis.

Locally advanced and advanced breast carcinomas may present with elevated levels of D-dimers, indicating a compensated state of DIC. Detection of D-Dimers may offer a differential analysis over other laboratory tests for DIC. Whether D-Dimers can be used as a marker or guide to assess the metastatic potential of the disease needs to be evaluated by further large-scale studies. Drugs targeting the coagulation cascade may be used in the future to reduce the metastatic potential or reduce the burden of the disease.^[37]

These findings highlight the potential of these biomarkers in enhancing risk stratification and guiding personalized treatment strategies for breast cancer patients. In recent years, bioinformatic analysis has advanced rapidly, and the adoption of bioinformatic approaches to analyze the favorable and unfavorable effects of platelets on cancer will undoubtedly aid the development and improvement of selectively targeted interventions.