Thrombosis in Cancer: Research Priorities Identified by a National Cancer Institute/National Heart, Lung, and Blood Institute Strategic Working Group

Comparison of the prognosis of symptomatic cerebral infarction and pulmonary embolism in patients with advanced non-small cell lung cancer

BACKGROUND

Lung cancer patients face a high risk of thromboembolism (TE), which is considered to be a poor prognostic factor. However, the impact of symptomatic cerebral infarction (CI) and pulmonary embolism (PE) on the prognosis of advanced non-small cell lung cancer (NSCLC) patients is not fully understood.

METHODS

We retrospectively identified 46 patients with advanced NSCLC who developed symptomatic CI or PE at five hospitals in Japan between January 2010 and December 2019. Prognosis and biomarker levels after incident CI and PE were investigated.

RESULTS

Of the 46 patients, 36 developed symptomatic CI, and 10 developed symptomatic PE. The median follow-up duration after incident CI and PE was 18.2 months. Although the proportion of Common Terminology Criteria for Adverse Events grade 4 tended to be higher in patients with PE than in those with CI (30% vs. 11%, p = 0.16), the overall survival (OS) after incident TE tended to be worse in patients with CI than in those with PE (median 2.3 months vs. 9.1 months, log-rank test p = 0.17). Multivariate analysis showed that OS after CI was worse in patients with high D-dimer (DD) levels than in those with low DD levels at the time of incident CI (median 1.3 months vs. 8.3 months, log-rank p < 0.001).

CONCLUSIONS

This retrospective study demonstrated that the prognosis of patients tended to be poorer after CI than after PE. The DD levels at the time of incident CI might be a promising predictor of clinical outcomes in advanced NSCLC patients who develop CI.

Targeting Platelet Activation Pathways to Limit Tumour Progression: Current State of Affairs

The association between cancer and a hypercoagulatory environment is well described. Thrombotic complications serve not only as a major mortality risk but the underlying molecular structure and function play significant roles in enhancing tumour progression, which is defined as the tumour's capacity to survive, invade and metastasise, amongst other hallmarks of the disease. The use of anticoagulant or antiplatelet drugs in cardiovascular disease lessens thrombotic effects, but the consequences on tumour progression require interrogation. Therefore, this review considered developments in the management of platelet activation pathways (thromboxane, ADP and thrombin), focusing on the use of Aspirin, Clopidogrel and Atopaxar, and their potential impacts on tumour progression. Published data suggested a cautionary tale in ensuring we adequately investigate not only drug-drug interactions but also those unforeseen reciprocal interactions between drugs and their targets within the tumour microenvironment that may act as selective pressures, enhancing tumour survival and progression.

Development of Monoclonal Antibody PMab-269 Against California Sea Lion Podoplanin

The development of protein-specific antibodies is essential for understanding a wide variety of biological phenomena. Parasitic and viral infections and cancers are known to occur within California sea lion (Zalophus californianus) populations. However, sensitive and specific monoclonal antibodies (mAbs) for the pathophysiological analysis of California sea lion tissues have not yet been developed. A type I transmembrane glycoprotein, podoplanin (PDPN), is a known diagnostic marker of lymphatic endothelial cells. We have previously developed several anti-PDPN mAbs in various mammalian species, with applications in flow cytometry, Western blotting, and immunohistochemistry. In this study, we established a novel mAb against California sea lion PDPN (seaPDPN), clone PMab-269 (mouse IgG₁, kappa), using a Cell-Based Immunization and Screening method. PMab-269 is specifically detected in seaPDPN-overexpressed Chinese hamster ovary (CHO)-K1 cells using flow cytometry and Western blotting. Moreover, PMab-269 clearly identified pulmonary type I alveolar cells, renal podocytes, and colon lymphatic endothelial cells in California sea lion tissues using immunohistochemistry. These findings demonstrate the usefulness of PMab-269 for the pathophysiological analysis of lung, kidney, and lymphatic tissues of the California sea lion.

Systematic review of observational studies reporting antiphospholipid antibodies in patients with solid tumors

This review summarizes the evidence on antiphospholipid (aPL) antibodies and related thromboembolic events in patients with solid tumors. Data sources included Medline, EMBASE, Web of Science, PubMed ePubs, and the Cochrane Central Register of Controlled Trials through August 2019 without restrictions. Observational studies that evaluated patients with solid tumors for the presence of aPL antibodies were included. Data were extracted and quality was assessed by one reviewer and cross-checked by another. Thirty-three studies were identified. Gastrointestinal (GI) and genitourinary (GU) cancers were the most frequently reported. Compared with healthy patients, patients with GI cancer were more likely to develop anticardiolipin antibodies (risk ratio [RR], 5.1; 95% confidence interval [CI], 2.6-9.95), as were those with GU (RR, 7.3; 95% CI, 3.3-16.2) and lung cancer (RR, 5.2; 95% CI, 1.3-20.6). The increased risk for anti-β2-glycoprotein I or lupus anticoagulant was not statistically significant. Patients with lung cancer who had positive aPL antibodies had higher risk of developing thromboembolic events than those who had negative antibodies (RR, 3.8%; 95% CI, 1.2-12.2), while the increased risk in patients with GU cancer was not statistically significant. Deaths due to thromboembolic events were more common among patients with lung cancer who had elevated aPL antibodies. A limitation of this review is that the results are contingent on the reported information. We found an increased risk of developing aPL antibodies in patients with GI, GU, and lung cancers resulting in thromboembolic events and death. Further studies are needed to better understand the pathogenesis and development of aPL antibodies in cancer.

High discrepancy in thrombotic events in non-small cell lung cancer patients with different genomic alterations

Background

Acute complications, such as venous thromboembolism (VTE), are common in patients with advanced severe lung cancers. However, current VTE risk scores cannot adequately identify high-risk patients with non-small cell lung cancer (NSCLC). The study proposed to elucidated the incidence of thromboembolism (TE) in patients with different oncogenic aberrations and the impact of these aberrations on the efficacy of targeted therapy in patients with NSCLC.

Methods

A systemic review was conducted in Web of Science, PubMed, Embase and the Cochrane Library to evaluate the incidence of TE in different molecular subtypes of NSCLC. Data from patients diagnosed of advanced NSCLC who harboring anaplastic lymphoma kinase (ALK) or ROS proto-oncogene 1 receptor tyrosine kinase (ROS1) rearrangements since 2016 to 2019 were also retrospectively collected. A meta-analysis with random-effects model, sensitivity analysis and publication bias were performed. The principal summary measure was incidence of thrombotic events in NSCLC patients. And the efficacy of tyrosine kinase inhibitor (TKI) therapy was compared between the two subgroups.

Results

A total of 5,767 cases from 20 studies were included in the analysis of the incidence of thrombosis in patients with different oncogenic alterations. The pooled analysis showed a higher risk of thrombosis in ROS1-fusion types (41%, 95% CI: 35-47%) and ALK-fusion types (30%, 95% CI: 24-37%) than in EGFR-mutation (12%, 95% CI: 8-17%), KRAS-mutation (25%, 95% CI: 13-50%), and wild-type (14%, 95% CI: 10-20%) cases. A high prevalence of thrombosis (ALK: 24.4%; ROS1: 32.6%) was observed in the Shanghai Pulmonary Hospital (SPH) cohort of 224 patients with ALK or ROS1 fusion. Furthermore, patients with embolism had significantly shorter progression-free survival (PFS) after TKI therapy than those without embolism, both in the ALK+ cohort (5.6 vs. 12.9 months, P<0.0001) and in the ROS1+ cohort (9.6 vs. 17.6 months, P=0.0481).

Conclusions

NSCLC patients with ALK/ROS1 rearrangements are more likely to develop thrombosis than patients with other oncogenic alterations. Thrombosis may also be associated with an inferior response and PFS after TKI therapy.

Pretreatment plasma d-dimer levels as an independent prognostic factor for overall survival among patients with advanced non-small-cell lung cancer

OBJECTIVE

To evaluate the prognostic accuracy of d-dimer levels for advanced non-small-cell lung cancer (NSCLC).

METHODS

This retrospective cohort study included 651 patients initially diagnosed with advanced NSCLC. Patients with d-dimer levels ≥0.5 mg/L were included in the high d-dimer group, whereas patients with lower levels were included in the normal group. Cumulative survival was estimated using Kaplan-Meier curves and compared using the log-rank test. Multivariate analyses were performed using the Cox proportional hazards model.

RESULTS

The median plasma d-dimer level in the study cohort was 0.61 ± 0.49 mg/L. d-dimer levels were elevated in 60.98% of patients, and 80.1% of such patients had adenocarcinoma. Univariate and multivariate analyses identified d-dimer content as an independent factor for the prognosis of NSCLC (hazard ratio [HR] = 1.54, 95% confidence interval [CI] = 1.19-1.98). Kaplan-Meier analysis revealed that high plasma d-dimer levels were associated with shorter overall survival (HR = 1.48, 95% CI = 1.19-1.84). In addition, the receipt of <2 lines of treatment was associated with a higher risk of death than the receipt of >2 lines.

CONCLUSION

The present results imply that pretreatment plasma d-dimer levels could represent a prognostic factor for advanced NSCLC.

Platelet-T cell aggregates in lung cancer patients: Implications for thrombosis

Platelet-leukocyte aggregates (PLAs) are associated with increased thrombosis risk. The influence of PLA formation is especially important for cancer patients, since thrombosis accounts for approximately 10% of cancer-associated deaths. Our objective was to characterize and quantify PLAs in whole blood samples from lung cancer patients compared to healthy volunteers with the intent to analyze PLA formation in the context of lung cancer-associated thrombosis. Consenting lung cancer patients (57) and healthy volunteers (56) were enrolled at the Dana Cancer Center at the University of Toledo Health Science Campus. Peripheral blood samples were analyzed by flow cytometry. Patient medical history was reviewed through electronic medical records. Most importantly, we found lung cancer patients to have higher percentages of platelet-T cell aggregates (PTCAs) than healthy volunteers among both CD4+ T lymphocyte and CD8+ T lymphocyte populations. Our findings demonstrate that characterization of PTCAs may have clinical utility in differentiating lung cancer patients from healthy volunteers and stratifying lung cancer patients by history of thrombosis.

Extracellular Vesicles in Cancer: Purpose and Promise

Extracellular vesicles refer collectively to a heterogeneous group of membrane-bound vesicles released from cells and loaded with bioactive proteins, nucleic acids, and lipids. The concept of extracellular vesicles has rapidly evolved from once being viewed as cellular debris to their recognition as packets of cellular information with considerable promise for clinical applications as biomarker platforms and therapeutic vehicles. These shed vesicles have emerged as critical mediators of intercellular communication in both local and distant microenvironments during normal physiological processes, as well as in orchestrating systemic pathophysiological events in disease. This mode of cellular crosstalk is particularly relevant to modulating the tumor microenvironment and orchestrating paths of least resistance during metastases. Here, we describe recent advances for the roles of extracellular vesicles in tumor progression and their potential as disease biomarkers.

Pathophysiology 2: The Role of Platelets in Cancer Biology

For over 100 years, a link has been recognized between thrombosis and cancer. However, whether this was a causal or correlational relationship was debated. It is now well established that cancer and thrombosis are mechanistically related in intricate ways and can directly fuel each other. Here, we present an historical perspective of platelets and how their physiological function in hemostasis can contribute to tumor development and metastasis. This emerging field has garnered great interest as aspirin therapy has been proposed as a prevention strategy for some malignancies. We highlight the advances that have been made, presenting platelets as a key component that supports many of the hallmarks of cancer that have been described and conclude with future directions and studies that are needed to clarify the role of platelets in cancer and solidify platelet modulating therapies within oncology.

Mechanisms coupling thrombin to metastasis and tumorigenesis

The association of malignancy and thrombophilia is bidirectional, as evidenced by four decades of studies in animal models showing that hemostatic system components support cancer progression. Consistent with this view, clinical studies have suggested that anticoagulants not only limit thromboembolic complications associated with cancer, but also improve survival by impeding cancer progression, and may even prevent the development of cancer. In order to fully capitalize on this association, a detailed understanding of the mechanisms coupling hemostatic factors to cancer pathogenesis is required. Multiple studies have shown that thrombin-mediated procoagulant functions strongly promote metastatic potential. In particular, the platelet/fibrin(ogen) axis has been shown to protect newly formed micrometastases from innate immune surveillance, contribute to creation of a metastatic niche by recruitment of prometastatic inflammatory cells, and promote the epithelial to mesenchymal transition of metastatic cells. Thrombin-mediated functions have also been shown to support tumor growth in some contexts, and have even been linked to tumorigenesis in the setting of inflammation-driven colon cancer. Here, local thrombin-mediated extravascular fibrin deposition, and specifically fibrin-α_Mβ₂ integrin interaction, push intestinal inflammatory cells toward a pro-tumorigenic phenotype, resulting in the elaboration of key cytokines and growth factors that support the proliferation and survival of transformed intestinal epithelial cells. These studies reveal that hemostatic factors can serve as a bridge between pathological inflammation and the development of cancer. As a large proportion of cancers are caused by pathological inflammation, these studies suggest that therapies targeting the nexus between hemostasis and inflammation could be used to prevent cancer development.

Cancer-associated thrombosis in patients with implanted ports: a prospective multicenter French cohort study (ONCOCIP)

The incidence of venous thromboembolism is high in patients with a solid tumor and implanted port in the real-life practice setting. The risk factors for catheter-related thrombosis differ from those for venous thromboembolism unrelated to the catheter.

Platelet-activating factor podoplanin: from discovery to drug development

Tumor cell-induced platelet aggregation facilitates hematogenous metastasis by promoting tumor embolization, preventing immunological assaults and shear stress, and the platelet-releasing growth factors support tumor growth and invasion. Podoplanin, also known as Aggrus, is a type I transmembrane mucin-like glycoprotein and is expressed on wide range of tumor cells. Podoplanin has a role in platelet aggregation and metastasis formation through the binding to its platelet receptor, C-type lectin-like receptor 2 (CLEC-2). The podoplanin research was originally started from the cloning of highly metastatic NL-17 subclone from mouse colon 26 cancer cell line and from the establishment of 8F11 monoclonal antibody (mAb) that could neutralize NL-17-induced platelet aggregation and hematogenous metastasis. Later on, podoplanin was identified as the antigen of 8F11 mAb, and its ectopic expression brought to cells the platelet-aggregating abilities and hematogenous metastasis phenotypes. From the 8F11 mAb recognition epitopes, podoplanin is found to contain tandemly repeated, highly conserved motifs, designated platelet aggregation-stimulating (PLAG) domains. Series of analyses using the cells expressing the mutants and the established neutralizing anti-podoplanin mAbs uncovered that both PLAG3 and PLAG4 domains are associated with the CLEC-2 binding. The neutralizing mAbs targeting PLAG3 or PLAG4 could suppress podoplanin-induced platelet aggregation and hematogenous metastasis through inhibiting the podoplanin–CLEC-2 binding. Therefore, these domains are certainly functional in podoplanin-mediated metastasis through its platelet-aggregating activity. This review summarizes the platelet functions in metastasis formation, the role of platelet aggregation-inducing factor podoplanin in pathological and physiological situations, and the possibility to develop podoplanin-targeting drugs in the future.

Randomized phase III trial of low-molecular-weight heparin enoxaparin in addition to standard treatment in small-cell lung cancer: the RASTEN trial

Background

Coagulation activation and venous thromboembolism (VTE) are hallmarks of malignant disease and represent a major cause of morbidity and mortality in cancer. Coagulation inhibition with low-molecular-weight heparin (LMWH) may improve survival specifically in small-cell lung cancer (SCLC) patients by preventing VTE and tumor progression; however, randomized trials with well-defined patient populations are needed to obtain conclusive data. The aim of RASTEN was to investigate the survival effect of LMWH enoxaparin in a homogenous population of SCLC patients.

Patients and methods

We carried out a randomized, multicenter, open-label trial to investigate the addition of enoxaparin at a supraprophylactic dose (1 mg/kg) to standard treatment in patients with newly diagnosed SCLC. The primary outcome was overall survival (OS), and secondary outcomes were progression-free survival (PFS), incidence of VTE and hemorrhagic events.

Results

In RASTEN, 390 patients were randomized over an 8-year period (2008-2016), of whom 186 and 191 were included in the final analysis in the LMWH and control arm, respectively. We found no evidence of a difference in OS or PFS by the addition of enoxaparin [hazard ratio (HR), 1.11; 95% confidence interval (CI) 0.89-1.38; P = 0.36 and HR, 1.18; 95% CI 0.95-1.46; P = 0.14, respectively]. Subgroup analysis of patients with limited and extensive disease did not show reduced mortality by enoxaparin. The incidence of VTE was significantly reduced in the LMWH arm (HR, 0.31; 95% CI 0.11-0.84; P = 0.02). Hemorrhagic events were more frequent in the LMWH-treated group but fatal bleedings occurred in both arms.

Conclusion

LMWH enoxaparin in addition to standard therapy did not improve OS in SCLC patients despite being administered at a supraprophylactic dose and despite resulting in a significant reduction in VTE incidence. Addition of LMWH cannot be generally recommended in the management of SCLC patients, and predictive biomarkers of VTE and LMWH-associated bleeding in cancer patients are warranted.

Management of cancer-associated venous thromboembolism - a case-based practical approach

In patients with solid tumours or haematological malignancies, venous thromboembolism (VTE) is a leading cause of death and significantly contributes to morbidity and healthcare resource utilization. Current practice guidelines recommend long-term anticoagulation with low-molecular-weight heparin (LMWH) as the treatment of choice for cancer-associated VTE, based on clinical trial data showing an overall improved safety and efficacy profile of LMWH compared to vitamin K antagonists. However, several open questions remain, e. g. with regard to the intensity and duration of LMWH therapy; moreover, recent real-world evidence indicates that adherence to parenteral anticoagulation with LMWH over the course of treatment is poor in clinical practice. In this regard, the direct oral factor Xa or thrombin inhibitors (DOACs) have emerged as potential alternatives in the management of patients with cancer-associated VTE, albeit findings from randomized controlled studies with a direct head-to-head comparison of DOACs with LMWH, the current standard of care, are still lacking. Based on the case of a lymphoma patient experiencing symptomatic pulmonary embolism during immunochemotherapy, this article aims at both highlighting the current state-of-the-art approach to cancer-associated VTE and pointing out some of the unresolved, controversial issues clinicians have to face when taking care of haematology and oncology patients with already established or with high risk of developing VTE. These issues include the management of patients with incidental pulmonary embolism or thrombocytopenia, the use of DOACs, and the initiation of pharmacological thromboprophylaxis in non-surgical cancer patients.

Incidence of venous thromboembolic events in enhanced recovery after surgery for colon cancer: a retrospective, population-based cohort study

AIM

Both the Danish and the National Institute of Clinical Excellence (NICE) guidelines recommend prolonged thromboprophylaxis (PT) with low-molecular-weight heparin (LMWH) for 28 days postoperatively after elective surgery for colon cancer. The evidence relies on data from two randomized clinical trials (RCTs) that included not only colon cancers but also other abdominal cancers or benign colorectal diseases. Neither of those studies investigated the risk of venous thromboembolism (VTE) under enhanced recovery after surgery (ERAS). We aim to describe the risk of VTE and estimate the cost of preventing one case of VTE by PT under ERAS.

METHOD

This was a retrospective study of 2230 patients undergoing elective surgery for colon cancer Stage I-III in the Capital Region of Denmark, 1 June 2008 to 31 December 2013. Patients who were discharged on postoperative day 28 or later, died during admission or were discharged with a vitamin K antagonist, novel oral anticoagulants or LMWH were excluded. Patients with rectal cancer only were not included. End-points were symptomatic VTE diagnosed within 60 days postoperatively.

RESULTS

Three-hundred and thirty patients were excluded. For the remaining 1893, the median length of stay (LOS) was 4 [interquartile range (IQR): 3-5] days. Of these 1893 patients, four (0.20%) experienced a nonfatal symptomatic VTE. All four patients had other postoperative complications before the VTE. The cost of each symptomatic VTE prevented is estimated to be between £63 709 and £111 455 when medication and home-care nursing are included.

CONCLUSION

The risk of symptomatic VTE after uncomplicated, elective surgery for colon cancer with ERAS seems negligible and the cost-effectiveness of PT to prevent one symptomatic VTE seems questionable.

Platelet count as a predictor of metastasis and venous thromboembolism in patients with cancer

Platelets are anucleate cells in the blood at concentrations of 150,000 to 400,000 cells/µL and play a key role in hemostasis. Several studies have suggested that platelets contribute to cancer progression and cancer-associated thrombosis. In this review, we provide an overview of the biochemical and biophysical mechanisms by which platelets interact with cancer cells and review the evidence supporting a role for platelet-enhanced metastasis of cancer, and venous thromboembolism (VTE) in patients with cancer. We discuss the potential for and limitations of platelet counts to discriminate cancer disease burden and prognosis. Lastly, we consider more advanced diagnostic approaches to improve studies on the interaction between the hemostatic system and cancer cells.

Incidence of Venous Thromboembolism by Type of Gynecologic Malignancy and Surgical Modality in the National Surgical Quality Improvement Program

BACKGROUND

Women with gynecologic cancer are at higher risk of venous thromboembolism (VTE) due to malignancy, pelvic surgery, increased age, and frequently comorbidities. The rate of VTE among different gynecologic cancers and relative to benign gynecologic surgeries has not been reported in a nationally representative cohort.

METHODS

Using the American College of Surgeons National Surgical Quality Improvement Program database, gynecologic surgeries were identified retrospectively from 2006 to 2012. Clinical characteristics, surgical procedures, and 30-day postoperative complications were abstracted. Multivariable logistic regression models were performed.

RESULTS

Of all gynecologic surgeries (n = 104,368), 11,427 were performed for malignancy: 2.7% (n = 2800) for ovarian cancer, 6.8% (n = 7114) for uterine cancer, 1.0% (n = 1026) for cervical cancer, and 0.5%(n = 487) for vulvar cancer. 202 (1.8%) patients experienced a VTE. Ovarian cancer had a deep venous thrombosis and pulmonary embolism rates of 1.6% and 1.5% compared with uterine cancer, 0.8% and 0.8%, respectively. Ovarian cancer patients were 1.8 (95% confidence interval [CI], 1.19-2.65) times more likely to have a deep venous thrombosis and 1.7 (95% CI, 1.11-2.51) times more likely to have a pulmonary embolism than patients with uterine cancer. Compared with all gynecologic cancer surgeries, ovarian cancer patients were 1.5 times more likely to have a VTE (95% CI, 1.10-2.16). Patients undergoing minimally invasive surgery were 64% less likely to have a VTE regardless of malignancy site; however, if they had disseminated disease, they remained at higher risk of VTE (odds ratio, 5.96; P = 0.027).

CONCLUSIONS

Of gynecologic cancer surgeries, ovarian cancer patients had the highest rate of VTE. Venous thromboembolism rates were lower in those who had minimally invasive surgery but remained higher in those with disseminated disease.

FOTROCAN Delphi consensus statement regarding the prevention and treatment of cancer-associated thrombosis in areas of uncertainty and low quality of evidence

INTRODUCTION

Decision-making in cancer-related venous thromboembolism (VTE) is often founded on scant lines of evidence and weak recommendations. The aim of this work is to evaluate the percentage of agreement surrounding a series of statements about complex, clinically relevant, and highly uncertain aspects to formulate explicit action guidelines.

MATERIALS AND METHODS

Opinions were based on a structured questionnaire with appropriate scores and were agreed upon using a Delphi method. Questions were selected based on a list of recommendations with low evidence from the Spanish Society of Oncology Clinical Guideline for Thrombosis. The questionnaire was completed in two iterations by a multidisciplinary panel of experts in thrombosis.

RESULTS

Of the 123 statements analyzed, the panel concurred on 22 (17%) and another 81 (65%) were agreed on by qualified majority, including important aspects of long-term and prolonged anticoagulation, major bleeding and rethrombosis management, treatment in special situations, catheter-related thrombosis and thromboprophylaxis. Among them, the panelists agreed the incidental events should be equated to symptomatic ones, long-term and extended use of full-dose low-molecular weight heparin, and concluded that the Khorana score is not sensitive enough to uphold an effective thromboprophylaxis strategy.

CONCLUSION

Though the level of consensus varied depending on the scenario presented, overall, the iterative process achieved broad agreement as to the general treatment principles of cancer-associated VTE. Clinical validation of these statements in genuine practice conditions would be useful.

Thromboembolic Disease in Patients with Metastatic Femoral Lesions: A Comparison Between Prophylactic Fixation and Fracture Fixation

BACKGROUND

We are not aware of any previous studies that have compared the rate of venous thromboembolic events in patients who underwent prophylactic intramedullary nailing because of an impending fracture with the rate in patients who underwent intramedullary nailing after a pathological fracture. The objective of the present study was to determine if the rate of venous thromboembolic events varies between patients who are managed with prophylactic fixation and those who are managed with fixation after a pathological fracture.

METHODS

We performed a retrospective comparative study in which the Nationwide Inpatient Sample database was used to identify all patients who had undergone femoral stabilization, either for a pathological femoral fracture or for prophylactic fixation of femoral metastatic lesion, over a period of 10 consecutive years (between 2002 and 2011) in the United States. Demographic data, comorbidities, venous thromboembolic event rates, and other common postoperative complications were compared between the 2 groups.

RESULTS

Patients who were managed with prophylactic fixation had significantly higher rates of pulmonary embolism (p < 0.001; adjusted odds ratio, 2.1) and deep-vein thrombosis (p = 0.03; adjusted odds ratio, 1.5). Patients who were managed with fixation after a pathological fracture had a significantly greater need for blood transfusion, higher rates of postoperative urinary tract infection, and a decreased likelihood of being discharged to home (p < 0.001 for all).

CONCLUSIONS

Patients with metastatic disease who undergo prophylactic intramedullary nailing have higher observed rates of venous thromboembolic events than those who undergo nailing for the treatment of a pathological fracture and should be actively and vigilantly managed in the postoperative period.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Cancer and Thrombosis: The Platelet Perspective

Platelets are critical to hemostatic and immunological function, and are key players in cancer progression, metastasis, and cancer-related thrombosis. Platelets interact with immune cells to stimulate anti-tumor responses and can be activated by immune cells and tumor cells. Platelet activation can lead to complex interactions between platelets and tumor cells. Platelets facilitate cancer progression and metastasis by: (1) forming aggregates with tumor cells; (2) inducing tumor growth, epithelial-mesenchymal transition, and invasion; (3) shielding circulating tumor cells from immune surveillance and killing; (4) facilitating tethering and arrest of circulating tumor cells; and (5) promoting angiogenesis and tumor cell establishment at distant sites. Tumor cell-activated platelets also predispose cancer patients to thrombotic events. Tumor cells and tumor-derived microparticles lead to thrombosis by secreting procoagulant factors, resulting in platelet activation and clotting. Platelets play a critical role in cancer progression and thrombosis, and markers of platelet-tumor cell interaction are candidates as biomarkers for cancer progression and thrombosis risk.