Factor V Leiden mutation and thromboembolism risk in women receiving adjuvant tamoxifen for breast cancer

Hemostatic imbalance induced by tamoxifen in estrogen receptor-positive breast cancer patients: An observational study

BACKGROUND

Estrogen receptor (ER)-positive (ER+) breast cancer accounts for approximately 75% of all breast cancers. Tamoxifen, a selective estrogen receptor modulator, is the standard adjuvant treatment. Although better tolerated than aromatase inhibitors, tamoxifen increases the risk of venous thromboembolism (VTE) 1.4-fold.

AIM

To assess the hemostatic imbalance induced by tamoxifen in adjuvant treatment of ER+ breast cancer.

METHOD

Twenty-five patients in remission from ER+ breast cancer under tamoxifen were included. One hundred and thirty one age- and BMI-matched healthy controls were included to establish reference ranges of thrombin generation assay (TGA) parameters. TGA was performed in the absence and presence of exogenous activated protein C (APC) to calculate the normalized APC sensitivity ratio (nAPCsr), a marker of APC resistance.

RESULTS

All TG parameters except the endogenous thrombin potential (ETP) (-APC) were significantly impacted by tamoxifen (p < 0.001). In absence of APC, regardless of TGA parameters, at least 50% of results were outside the reference ranges except for ETP, which was above the upper reference limit in only two individuals. The most impacted parameter was the Peak Height with 52% (-APC) and 80% (+APC) of results above the upper reference range limit, respectively. The nAPCsr was significantly higher in tamoxifen users (mean ± standard deviation = 3.18 ± 0.91) compared to the control group (2.19 ± 0.92, p < 0.0001).

CONCLUSION

This observational study showed that patients in remission from ER+ breast cancer taking tamoxifen had altered thrombin generation, as well as an acquired APC resistance. Moreover, this is the first study using the validated ETP-based APC resistance assay in tamoxifen-treated patients.

The Contribution of Inherited Thrombophilia to Venous Thromboembolism in Cancer Patients

Although the relationship between venous thromboembolism (VTE) and cancer has been a subject of study, knowledge of the contribution of thrombophilia to thrombosis in patients with cancer is still very limited. The aim of this article is to collect present knowledge on the contribution of inherited thrombophilia to VTE in cancer patients. We performed a search in Google Scholar and PubMed and selected 21 from 76 returned articles. Then we made a narrative review of the selected articles. We describe 11 studies on the contribution of inherited thrombophilia to VTE in cancer patients in general and 10 on that contribution in specific types of cancer: 1 in colorectal cancer, 4 in breast cancer, 1 in gynecologic cancer and 4 in hematopoietic malignancies. All studies investigate the relation of factor V Leiden (FVL) to VTE, 13 that of the prothrombin G20210A mutation (PTG20210A) and 7 studies also investigate other inherited thrombophilias, such methylenetetrahydrofolate reductase gene mutations, although only 2 investigate the contribution of deficiencies of the natural anticoagulants. Studies are very heterogeneous, in design and sample size and conclusions differ considerably. There is no consensus on the contribution of inherited thrombophilia to VTE in cancer patients except for acute lymphoblastic leukemia in children. Probably, that contribution is not the same for all types of cancer and more studies are needed to bring more knowledge on this subject.

[Venous thromboembolism and breast cancer]

Breast cancer is the most common cancer in women. Patients with breast cancer have a 4-fold increased risk of venous thromboembolism (VTE) compared to age- and sex-matched controls without cancer. VTE remains the second leading cause of death in cancer patients and an independent risk factor for mortality. In women with breast cancer, the main risk factors for developing VTE are increasing age, obesity, disease stage, central catheter placement and cancer treatments, including surgery, chemotherapy, hormonotherapy and cyclin-dependent kinase 4/6 inhibitors. In women receiving tamoxifen, the risk of VTE is particularly increased within the first 6 months after initiation of hormonotherapy, although some evidence suggests that this risk may persist through the first 2 years of treatment. The risk of VTE appears to be lower in patients receiving aromatase inhibitors. In breast cancer patients receiving cyclin-dependent kinase 4/6 inhibitors, the rate of VTE is approximately 6%. Current clinical practice guidelines for the treatment and prevention of VTE in patients with cancer suggest that thromboprophylaxis should not be used routinely in ambulatory cancer patients receiving chemotherapy or hormonotherapy. The risk-benefit ratio of thromboprophylaxis should be assessed on a case-by-case basis and be the subject of multidisciplinary discussion.

The Saudi Consensus for the Management of Cancer-Associated Thromboembolism: A Modified Delphi-Based Study

Background  Cancer is a well-known risk factor of preventable thromboembolic disease. This study aims to provide guidance on the prevention and management of cancer-associated thrombosis (CT) that tailors prophylactic and therapeutic options for medical and surgical oncology patients presenting to health care settings in Saudi Arabia. Methods  The present consensus was developed in concordance with the modified Delphi-based approach, which incorporates a face-to-face meeting between two voting rounds to gain experts' feedback on the proposed statements. All experts were either oncologists, hematologists, or hemato-oncologist with an active clinical and research profile in hemato-oncology. Results  The experts highlighted that the comparatively high incidence of inherited thrombophilia among the Saudi population may account for a higher CT burden in the Kingdom than in other parts of the world. However, due to the lack of literature that assesses CT in Saudi Arabia, primary venous thromboembolism prophylaxis should be tailored according to a valid risk assessment of cancer patients and should be implemented in routine practice. For hospitalized medical oncology patients, the experts agreed that prophylaxis with low-molecular-weight heparin (LMWH) should be offered, regardless of the presence of acute illness. For ambulatory medical oncology patients, LMWH or direct oral anticoagulants (DOACs) prophylaxis should be offered for high-risk patients. Concerning surgical patients, they agreed that all oncology patients undergoing surgery should be offered thromboprophylaxis. In terms of secondary prophylaxis, the experts recommended continuing a prophylactic dose of anticoagulant (LMWH or DOAC), for an appropriate period depending on the cancer type and stage. Finally, they also provided a set of statements on management of CT in Saudi Arabia. Conclusion  The present modified Delphi-based study combined the best available evidence and clinical experience with the current health care policies and settings in Saudi Arabia to build a consensus statement on the epidemiology, prevention, and management of CT.

Venous Thromboembolism in Women with Cancer with an Additional Focus on Breast and Gynecological Cancers

Cancer-associated venous thromboembolism (VTE) is common in women with cancer. Many clinical practice guidelines provide guidance for prevention and treatment; however, there are no specific recommendations for women. This is unfortunate because the proportion of women with breast- and gynecological cancers is high among patients with cancer-associated VTE. Thromboembolism often heralds cancer progression and poor prognosis and should—besides adequate anticoagulant management—also prompt reassessment and, if necessary, changes in cancer treatment. Recently, the new class of direct-acting oral anticoagulants (DOACs) has started to replace low-molecular-weight heparin as standard thromboprophylaxis and therapy in cancer patients. They are very effective, but they also carry a relevant risk of bleeding. Therefore, despite their ease of use, not every tumor patient qualifies for a DOAC, and this is especially true for gynecological tumor patients. Each prescription must be weighed individually. This review addresses specific aspects of VTE prophylaxis and management in women with cancer. Every physician who treats breast and gynecological cancers should be familiar with prophylaxis, diagnosis, and therapy of cancer-associated VTE. At the same time, patients should be informed by their physician what symptoms to look for and whom to contact if these symptoms occur, even outside of office hours and on weekends.

Impact of hereditary thrombophilia on cancer-associated thrombosis, tumour susceptibility and progression: A review of existing evidence

Venous thromboembolism (VTE) is a cardiovascular disorder frequently diagnosed among cancer patients. Aside from being common, VTE severely deteriorates the prognosis of these patients as they face a higher risk of morbidity and mortality, which makes clinical tools able to identify the patients more prompt to thrombogenesis very attractive. Over the years, several genetic polymorphisms have been linked with VTE susceptibility in the general population. However, their clinical usefulness as predictive biomarkers for cancer-related VTE is yet unclear. Furthermore, as a two-way association between cancer and VTE is well-recognized, with haemostatic components fuelling tumour progression, haemostatic gene polymorphisms constitute potential cancer predictive and/or prognostic biomarkers as well. Thus, in this article, we review the existing evidence on the role of these polymorphisms on cancer-related VTE and their impact on cancer onset and progression. Despite the promising findings, the existing studies had inconsistent results most likely due to their limited statistical power and population heterogeneity. Future studies are therefore required to clarify the role of these polymorphisms in setting of malignancy.

Risk factors associated with venous thromboembolism in breast cancer: a narrative review

PURPOSE

To date, there is no universally acceptable risk assessment tool in clinical practice that accurately estimates the risk of venous thromboembolism (VTE) in patients with breast cancer, despite the large number of published studies. Thus, the aim of this narrative review was to summarize the most relevant risk factors for VTE in these patients.

METHODS

We searched Ovid Embase and Ovid MEDLINE, from inception to March 26, 2021, to identify all articles that focused on breast cancer and multiple thromboembolic diseases. We also searched the references section of relevant articles to identify studies. We did not include case reports or case series with small sample size, N < 20.

RESULTS

VTE in patients with breast cancer was strongly associated with patient-, tumor-, and non-tumor-related risk factors, such as age, disease stage, central catheter placement, and chemotherapy and tamoxifen use, especially within 2 years of breast cancer diagnosis. CDK inhibitors are emerging factors that may also increase the risk of VTE.

CONCLUSIONS

The risk of VTE in patients with breast cancer depends on various patient-, tumor-, and non-tumor-related risk factors. Identifying these risk factors during breast cancer diagnosis and treatment is essential in developing a practical dynamic predictive tool that can help individualize strategies to prevent VTE.

Construction of Potential Gene Expression and Regulation Networks in Prostate Cancer Using Bioinformatics Tools

Objective

To identify the key genes involved in prostate cancer and their regulatory network.

Methods

The dataset of mRNA/miRNA transcriptome sequencing was downloaded from The Cancer Genome Atlas/the Gene Expression Omnibus database for analysis. The “edgeR” package in the R environment was used to normalize and analyze differentially expressed genes (DEGs) and miRNAs (DEmiRNAs). First, the PANTHER online tool was used to analyze the function enrichment of DEGs. Next, a protein-protein interaction (PPI) network was constructed using STRING and Cytoscape tools. Finally, miRNA-gene regulatory networks were constructed using the miRTarBase.

Results

We identified 4339 important DEGs, of which 2145 were upregulated (Up-DEGs) and 2194 were downregulated (Down-DEGs). Functional enrichment analysis showed that the Up-DEGs were related to the immune system and the cell cycle in prostate cancer, whereas the Down-DEGs were related to the nucleic acid metabolic process and metabolism pathways. Twelve core protein clusters were found in the PPI network. Further, the constructed miRNA-gene interaction network showed that 11 downregulated miRNAs regulated 16 Up-DEGs and 22 upregulated miRNAs regulated 22 Down-DEGs.

Conclusion

We identified 4339 genes and 70 miRNAs that may be involved in immune response, cell cycle, and other key pathways of the prostate cancer regulatory network. Genes such as BUB1B, ANX1A1, F5, HTR4, and MUC4 can be used as biomarkers to assist in the diagnosis and prognosis of prostate cancer.

Primary Thromboprophylaxis in Patients with Malignancies: Daily Practice Recommendations by the Hemostasis Working Party of the German Society of Hematology and Medical Oncology (DGHO), the Society of Thrombosis and Hemostasis Research (GTH), and the Austrian Society of Hematology and Oncology (ÖGHO)

Patients with cancer, both hematologic and solid malignancies, are at increased risk for thrombosis and thromboembolism. In addition to general risk factors such as immobility and major surgery, shared by non-cancer patients, cancer patients are exposed to specific thrombotic risk factors. These include, among other factors, cancer-induced hypercoagulation, and chemotherapy-mediated endothelial dysfunction as well as tumor-cell-derived microparticles. After an episode of thrombosis in a cancer patient, secondary thromboprophylaxis to prevent recurrent thromboembolism has long been established and is typically continued as long as the cancer is active or actively treated. On the other hand, primary prophylaxis, even though firmly established in hospitalized cancer patients, has only recently been studied in ambulatory patients. This recent change is mostly due to the emergence of direct oral anticoagulants (DOACs). DOACs have a shorter half-life than vitamin K antagonists (VKA), and they overcome the need for parenteral application, the latter of which is associated with low-molecular-weight heparins (LMWH) and can be difficult for the patient to endure in the long term. Here, first, we discuss the clinical trials of primary thromboprophylaxis in the population of cancer patients in general, including the use of VKA, LMWH, and DOACs, and the potential drug interactions with pre-existing medications that need to be taken into account. Second, we focus on special situations in cancer patients where primary prophylactic anticoagulation should be considered, including myeloma, major surgery, indwelling catheters, or immobilization, concomitant diseases such as renal insufficiency, liver disease, or thrombophilia, as well as situations with a high bleeding risk, particularly thrombocytopenia, and specific drugs that may require primary thromboprophylaxis. We provide a novel algorithm intended to aid specialists but also family practitioners and nurses who care for cancer patients in the decision process of primary thromboprophylaxis in the individual patient.

Assessment of genetic and non-genetic risk factors for venous thromboembolism in glioblastoma - The predictive significance of B blood group

INTRODUCTION

Venous thromboembolism (VTE) is a common problem among patients with glioblastoma multiforme (GBM) and with some other cancers. Here, we evaluated genetic and non-genetic potential risk factors for VTE among GBM patients.

MATERIALS AND METHODS

A cohort of 139 patients treated with concomitant radiotherapy and temozolomide were included in the study. Next generation sequencing and genotyping approaches were applied to assess genetic risk factors in the haemostatic system. Clinical data including surgery, reoperation as well as blood group and patient information such as age and gender were available from patient records. Logistic regression analysis was performed to asses VTE risk.

RESULTS

In the study 47 patients (34%) were diagnosed for VTE during the course of their disease. When genetic and non-genetic potential risk factors were evaluated, only B blood group was found to be significantly associated with VTE incidence (odds ratio [OR] = 6.91; confidence interval [CI] = 2.19-24.14; P = 0.001). In contrast, A and O blood groups did not correlate with VTE risk. Frontal lobe tumor location also seemed to slightly increase VTE risk compared to other brain sites (OR = 3.14; CI = 1.1-10.7) although the significance level was at borderline (P = 0.05). Current study identified B blood group as the component in non-O blood groups that is responsible for increased VTE risk.

CONCLUSION

In conclusion, these results suggest for the first time that B blood group is predictive for VTE incidence among patients with glioblastoma, information that may be potentially valuable when selecting GBM patients who are at risk for VTE for anticoagulant prophylaxis.

Personalized medicine in breast cancer: pharmacogenomics approaches

Abstract: Breast cancer is the fifth cause of cancer death among women worldwide and represents a global health concern due to the lack of effective therapeutic regimens that could be applied to all disease groups. Nowadays, strategies based on pharmacogenomics constitute novel approaches that minimize toxicity while maximizing drug efficacy; this being of high importance in the oncology setting. Besides, genetic profiling of malignant tumors can lead to the development of targeted therapies to be included in effective drug regimens. Advances in molecular diagnostics have revealed that breast cancer is a multifaceted disease, characterized by inter-tumoral and intra-tumoral heterogeneity and, unlike the past, molecular classifications based on the expression of individual biomarkers have led to devising novel therapeutic strategies that improve patient survival. In this review, we report and discuss the molecular classification of breast cancer subtypes, the heterogeneity resource, and the advantages and disadvantages of current drug regimens with consideration of pharmacogenomics in response and resistance to treatment.

Thrombotic Risk from Chemotherapy and Other Cancer Therapies

Cancer patients have an increased risk of thrombosis. The development of cancer thrombosis is dependent on a number of factors including cancer type, stage, various biologic markers, and the use of central venous catheters. In addition, cancer treatment itself may increase thrombotic risk. Tamoxifen increases the risk of venous thromboembolism (VTE) by two- to sevenfold, while an impact on risk of arterial thrombosis is uncertain. Immunomodulatory imide drugs (IMiDs) such as thalidomide and lenalidomide increase the risk of VTE in patients with multiple myeloma (MM) by about 10-40% when given in combination with glucocorticoids or other chemotherapy agents; the risk of VTE in MM patients treated with IMiD-containing regimens necessitates that such patients receive thromboprophylaxis with aspirin, low-molecular-weight heparin, or warfarin. Among cytotoxic chemotherapy agents, cisplatin, and to a lesser extent fluorouracil, has been described in association with thrombosis. L-asparaginase in treatment of acute lymphoblastic leukemia is significantly associated with increased thrombosis particularly affecting the CNS, which may be due to acquired antithrombin deficiency; at some centers, plasma infusions or antithrombin replacement is used to mitigate this. Bevacizumab, an inhibitor of vascular endothelial growth factor, increases arterial and possibly venous thrombotic risk, although the literature is conflicting about the latter. Supportive care agents in cancer care, such as erythropoiesis-stimulating agents, granulocyte colony stimulating factor, and steroids, also have some impact on thrombosis. This review summarizes the mechanisms by which these and other therapies modulate thrombotic risks and how such risks may be managed.

Endocrine therapy for breast cancer in the primary care setting

The treatment of hormone-positive breast cancer (bca) is a rapidly evolving field. Improvement in the understanding of the mechanisms of action and resistance to anti-hormonal therapy has translated, in the past decade, into multiple practice-changing clinical trials, with the end result of increased survivorship for patients with all stages of hormone-positive cancer. The primary care physician will thus play an increasing role in the routine care, surveillance, and treatment of issues associated with anti-hormonal therapy. The aim of the present review was to provide a focused description of the issues relevant to primary care, while briefly highlighting recent advances in the field of anti-hormonal therapy.

Key Points

■ Hormone-positive bca is the most prevalent form of bca and, compared with the other subtypes, is usually associated with better survival.■ Survivorship has significantly increased for all stages of hormone-positive bca, making the primary care physician a key player in the care of affected patients.■ The two most common classes of anti-hormonal agents used in these patients are selective estrogen receptor modulators and aromatase inhibitors. Each class of medication is associated with signature side effects.■ Within the past decade, multiple novel estrogen receptor blockers (for example, fulvestrant) and agents aimed at circumventing resistance to endocrine therapy [inhibitors of cyclin-dependent kinase 4/6 and of mtor (the mechanistic target of rapamycin)] have gained clinical ground. Understanding their side effects will be increasingly relevant to primary care physicians.■ Multidisciplinary care is always encouraged in the care of cancer patients receiving anti-hormonal therapy.

Risk of venous thromboembolism in association with factor V leiden in cancer patients - The EDITH case-control study

Background

Cancer and factor V Leiden mutation are both risk factors for venous thromboembolism (VTE). Cancer critically increases the thrombotic risk whereas Factor V Leiden is the most common pro-thrombotic mutation. The impact of the factor V Leiden on the risk of VTE in cancer patients remains uncertain.

Objective

To assess the impact of factor V Leiden mutation in cancer-associated thrombosis.

Methods

The EDITH hospital-based case-control study enrolled 182 patients with cancer and VTE as well as 182 control patients with cancer, matched for gender, age and cancer location, between 2000 and 2012, in the University Hospital of Brest. All cases and controls were genotyped for the factor V Leiden mutation and interviewed with a standardized questionnaire.

Results

Twenty one of 182 (11.5%) patients with cancer-associated thrombosis carried the factor V Leiden mutation and 4 of 182 (2.2%) controls with cancer but no venous thrombosis. In multivariate analysis including cancer stage and family history of VTE, cancer patients with factor V Leiden mutation had a seven-fold increased risk of venous thromboembolism (adjusted odds ratio [OR], 7.04; 95% CI, 2.01–24.63).

Conclusion

The pro-thrombotic Factor V Leiden mutation was found to be an independent additional risk factor for venous thromboembolism in cancer patients and might therefore be considered in the individual thrombotic risk assessment.

Polymorphisms of the coagulation system and risk of cancer

Hypercoagulability is a frequently finding in patients with cancer, and is associated with an increased risk of venous thrombosis (VT). Cancer-associated VT is associated with poor prognosis and represents the leading non-cancer cause of death among these patients. Conversely, patients experiencing VT are at increased risk of subsequent cancer, suggesting an epidemiological bidirectional link between cancer and hemostasis, and indicating a role of the hemostatic system in cancer development. How the coagulation system relates to cancer etiology at the genetic level is largely unexplored. Data on the association of polymorphisms in genes involved in coagulation with cancer development is important to clarify the role of the coagulation system in cancer pathogenesis. Effects of coagulation-related gene polymorphisms on cancer risk may possibly be translated into novel treatment- and prevention strategies of cancer-associated thrombosis and the cancer itself. This article reviews the current knowledge of the relation between polymorphisms in genes involved in coagulation and cancer risk in solid tumors.

Cancer-associated venous thromboembolism: Burden, mechanisms, and management

Venous thromboembolism (VTE) is a significant health problem in the general population but especially in cancer patients. In this review, we discuss the epidemiology and burden of the disease, the pathophysiology of cancer-associated VTE, and the clinical treatment options for both primary prevention and acute treatment. Overall, the development of VTE in cancer patients is related to increases in morbidity, mortality, and medical costs. However, the incidence of cancer-associated VTE varies due to patient-related factors (e.g. thrombophilia, comorbidities, performance status, history of venous diseases), tumour-related factors (e.g. cancer site, stage, grade), and treatment-related factors (e.g. surgery, chemotherapy, anti-angiogenesis treatment, hormonal and supportive treatment). Furthermore, blood count parameters (e.g. platelets and leukocytes) and biomarkers (e.g. soluble P-selectin and D-dimer) are predictive markers for the risk of VTE in cancer patients and have been used to enhance risk stratification. Evidence suggests that cancer itself is associated with a state of hypercoagulability, driven in part by the release of procoagulant factors, such as tissue factor, from malignant tissue as well as by inflammation-driven activation of endothelial cells, platelets, and leukocytes. In general, low-molecular-weight heparin (LWMH) monotherapy is the standard of care for the management of cancer-associated VTE, as vitamin K antagonists are less effective in cancer patients. Direct oral anticoagulants (DOACs) offer a potentially promising treatment option for cancer patients with VTE, but recommendations concerning the routine use of DOACs should await head-to-head studies with LMWH.

Management of chemotherapy-induced thromboembolism in breast cancer

Thromboembolic events are common in cancer patients and, apart from contributing to significant morbidity, are regarded as the second leading cause of death in this population. Breast cancer patients are considered low risk for venous thromboembolism; however, the presence of advanced disease and use of chemotherapy and/or other adjunct treatments significantly raises this risk by altering the balance of pro- and anti-coagulant proteins. Low molecular weight heparin is central to the management of venous thromboembolism in this context, whether for prophylaxis, acute management or prevention of recurrences. Risk stratification models need to be incorporated to guide decision making where available.

Factor V Leiden mutation increases the risk for venous thromboembolism in cancer patients - results from the Vienna Cancer And Thrombosis Study (CATS)

BACKGROUND

Patients with cancer are at an increased risk for venous thromboembolism (VTE). The risk varies markedly in different patient populations. Factor V (FV) Leiden is the most common genetic risk factor for VTE, and the impact of FV Leiden on cancer-associated thrombosis is not yet fully elucidated.

OBJECTIVE

To study the impact of FV Leiden on the risk of thrombosis in cancer patients.

METHODS

In the prospective observational Vienna Cancer And Thrombosis Study (CATS), 982 patients were included and were followed until occurrence of VTE or death, for a maximum period of 2 years. FV Leiden was determined by genotyping at inclusion. Main outcome measures were symptomatic or lethal objectively confirmed VTE.

RESULTS

Of the 982 patients, FV Leiden was diagnosed in 72 (7.3%, 70 were heterozygous and 2 were homozygous). Ten of 72 (13.9%) patients with FV Leiden developed VTE, whereas this was the case in 69 of 910 (7.6%) patients without FV Leiden. In multivariate analysis that included age, sex, different tumor types, tumor stage, newly diagnosed vs. recurrence of disease, and the treatment modalities, the hazard ratio was 2.0 (95% confidence interval 1.0-4.0). In Kaplan-Meier analysis, the probability for development of VTE was 13% in those with and 5.7% in those without FV Leiden after 6 months; after 1 year, the corresponding risks were 15% and 7.3%.

CONCLUSIONS

FV Leiden is a genetically determined and thus disease-independent parameter, which is associated with VTE in cancer patients and could therefore be used for individual risk assignment.

Factor V Leiden mutation and high FVIII are associated with an increased risk of VTE in women with breast cancer during adjuvant tamoxifen - results from a prospective, single center, case control study

BACKGROUND

Estimates of the risk ratio of tamoxifen-associated venous thromboembolism (VTE) in breast cancer patients range from 2.4 to 7.1. The occurrence of thrombosis in patients with breast cancer complicates the clinical condition and causes a change of treatment. Our study was conducted in order to investigate the influence of patient-related risk factors for thrombosis development in breast cancer patients whose treatment included adjuvant tamoxifen.

METHODS

The prospective, single center, case control study included 150 breast cancer women, 50 whom developed venous thrombosis during adjuvant tamoxifen and 100 whom did not have thrombosis, as a control group. Patient-related risk factors such as: age, body mass index, previous VTE, varicose veins, concomitant diseases, the presence of prothrombotic mutations (FV Leiden, FII G20210A) and FVIII activity were evaluated in both groups.

RESULTS

In respect of prothrombotic mutations, the FV Leiden mutation was present in a higher number of women from the VTE group (10/50 vs 7/100; P=0.020). Additionally, FVIII activity was significantly higher in the VTE group; median (IQR), of 1.79 (0.69) vs 1.45 (0.55); P<0.001 and more women in this group (24/50 vs 34/100) had increased FVIII activity; P=0.020. In those women with FVIII>1.5IU/ml, who were carriers of prothrombotic mutations, an OR of 3.76 (CI 95% 1.276-11.096; P=0.016) was obtained for VTE.

CONCLUSION

The results of our study showed that the factor V Leiden mutation and high FVIII are associated with an increased risk of VTE in women with breast cancer during adjuvant tamoxifen.

No increased venous thromboembolism risk in Asian breast cancer patients receiving adjuvant tamoxifen

Tamoxifen is an effective endocrine treatment for early breast cancer (EBC) but increases the risk of venous thromboembolism. Whether Asian EBC patients (pts) bear the same risk when treated with adjuvant tamoxifen is uncertain. EBC pts diagnosed between 2004 and 2009 were selected from a population database in Taiwan. The pts were followed up from the index date to December 31, 2011 to collect events of deep vein thrombosis (DVT) and pulmonary embolism (PE). Cumulative incidence rates and hazard ratios (HRs) were used to compare the risk between pts treated with and without tamoxifen. In addition, comorbidities were included in an adjusted model of the risk of DVT and PE. A total of 28,029 EBC pts, including 17,843 (63.8 %) in the tamoxifen group and 10,155 (36.2 %) in the nontamoxifen group, were analyzed. The 7-year cumulative incidence rates for DVT and PE were 2.58 and 0.32 % in the tamoxifen group and 2.51 and 0.32 % in the nontamoxifen group (P = 0.92 for DVT, P = 0. 65 for PE), respectively. The HR for the nonadjusted and adjusted models showed no differences in DVT and PE risks between the tamoxifen and nontamoxifen groups. The uterine cancer risk was significantly increased in the pts receiving tamoxifen (adjusted HR = 2.79, P < 0.001), suggesting tamoxifen compliance. The risks of developing DVT and PE are not increased in Asian EBC pts receiving adjuvant tamoxifen. Ethnicity differences should be considered when discussing optimal endocrine treatments with EBC pts.

Endocrine therapy toxicity: management options

Treatment with adjuvant endocrine therapy, including tamoxifen and the aromatase inhibitors, has resulted in notable improvements in disease-free and overall survival for patients with hormone receptor-positive breast cancer. Despite their proven benefit, however, adherence to and persistence with the medications is poor in part because of bothersome side effects that can negatively affect quality of life. Retrospective analyses have identified possible predictors of development of toxicity. Reports have also suggested that development of toxicity may be a biomarker of better response to therapy. In addition, there has been considerable research investment into the management of these side effects, which may lead to improved adherence and persistence with therapy. However, although notable advances have been made, much more remains to be done to provide patients with truly personalized therapy for hormone receptor-positive breast cancer.

Adjuvant therapy in breast cancer and venous thromboembolism

Breast cancer patients are considered to be at relatively low risk of developing a TEE. The highest incidence of VTE events occurs in metastatic breast cancer patients likely due to extension of disease, immobility for pathologic bone fractures, cancer cachexia and venous compression by the tumour mass. Although thrombosis is less common in patients with early stage cancer compared to those with more advanced disease, it does occur and is clinically challenging. The adjuvant setting is of particular interest in order to assess the specific thrombogenic potential of systemic chemotherapy, because of the low tumor burden with only microscopic tumor foci at the time of treatment administration. This review summarizes risk factors, incidence and strategies to avoid VTE in breast cancer patients receiving adjuvant therapy.

Pharmacogenomics of breast cancer therapy: an update

Clinical and histopathologic characteristics of breast cancer have long played an important role in treatment decision-making. Well-recognized prognostic factors include tumor size, node status, presence or absence of metastases, tumor grade, and hormone receptor expression. High tumor grade, presence of hormone receptors, and HER2-positivity are a few predictive markers of response to chemotherapy, endocrine manipulations, and anti-HER2 agents, respectively. However, there is much heterogeneity of outcomes in patients with similar clinical and pathologic features despite equivalent treatment regimens. Some of the differences in response to specific therapies can be attributed to somatic tumor characteristics, such as degree of estrogen receptor expression and HER2 status. In recent years, there has been great interest in evaluating the role that pharmacogenetics/pharmacogenomics, or variations in germline DNA, play in alteration of drug metabolism and activity, thus leading to disparate outcomes among patients with similar tumor characteristics. The utility of these variations in treatment decision-making remains debated. Here we review the data available to date on genomic variants that may influence response to drugs commonly used to treat breast cancer. While none of the variants reported to date have demonstrated clinical utility, ongoing prospective studies and increasing understanding of pharmacogenetics will allow us to better predict risk of toxicity or likelihood of response to specific treatments and to provide a more personalized therapy.

Estimation and testing of the relative risk of disease in case-control studies with a set of k matched controls per case with known prevalence of disease

The analysis of case-control studies with matched controls per case is well documented in the medical literature. Of primary interest is the estimation of the relative risk of disease. Matched case-control studies fall into two scenarios: the probability of exposure is constant within each of the case and control groups, or the probability of exposure varies within each group. Numerous estimation procedures have been developed for both scenarios. Often these procedures are developed under the rare disease assumption, where the relative risk of disease is approximated by the odds ratio. In this paper, without making the rare disease assumption, we develop consistent estimators of the relative risk of disease for both scenarios. Exact derivations of the relative risk of disease are provided. Estimators, confidence intervals, and test statistics for the relative risk of disease are developed. We then make the following observations based on extensive simulations. First, our estimators are as close or closer to the relative risk of disease than other estimators. Second, our estimators produce mean square errors for the relative risk of disease that are as good as or better than these other estimators. Third, our confidence intervals provide accurate coverage probabilities. Therefore, these new estimators, confidence intervals, and test statistics can be used to either estimate or test the relative risk of disease in matched case-control studies.

Factor V Leiden thrombophilia

Factor V Leiden is a genetic disorder characterized by a poor anticoagulant response to activated Protein C and an increased risk for venous thromboembolism. Deep venous thrombosis and pulmonary embolism are the most common manifestations, but thrombosis in unusual locations also occurs. The current evidence suggests that the mutation has at most a modest effect on recurrence risk after initial treatment of a first venous thromboembolism. Factor V Leiden is also associated with a 2- to 3-fold increased relative risk for pregnancy loss and possibly other obstetric complications, although the probability of a successful pregnancy outcome is high. The clinical expression of Factor V Leiden is influenced by the number of Factor V Leiden alleles, coexisting genetic and acquired thrombophilic disorders, and circumstantial risk factors. Diagnosis requires the activated Protein C resistance assay (a coagulation screening test) or DNA analysis of the F5 gene, which encodes the Factor V protein. The first acute thrombosis is treated according to standard guidelines. Decisions regarding the optimal duration of anticoagulation are based on an individualized assessment of the risks for venous thromboembolism recurrence and anticoagulant-related bleeding. In the absence of a history of thrombosis, long-term anticoagulation is not routinely recommended for asymptomatic Factor V Leiden heterozygotes, although prophylactic anticoagulation may be considered in high-risk clinical settings. In the absence of evidence that early diagnosis reduces morbidity or mortality, decisions regarding testing at-risk family members should be made on an individual basis.

Risk assessment models for cancer-associated venous thromboembolism

Venous thromboembolism (VTE) is common in cancer patients, and is associated with significant morbidity and mortality. Several factors, including procoagulant agents secreted by tumor cells, immobilization, surgery, indwelling catheters, and systemic treatment (including chemotherapy), contribute to an increased risk of VTE in cancer patients. There is growing interest in instituting primary prophylaxis in high-risk patients to prevent incident (first-time) VTE events. The identification of patients at sufficiently high risk of VTE to warrant primary thromboprophylaxis is essential, as anticoagulation may be associated with a higher risk of bleeding. Current guidelines recommend the use of pharmacological thromboprophylaxis in postoperative and hospitalized cancer patients, as well as ambulatory cancer patients receiving thalidomide or lenalidomide in combination with high-dose dexamethasone or chemotherapy, in the absence of contraindications to anticoagulation. However, the majority of cancer patients are ambulatory, and currently primary thromboprophylaxis is not recommended for these patients, even those considered at very high risk. In this concise review, the authors discuss risk stratification models that have been specifically developed to identify cancer patients at high risk for VTE, and thus might be useful in future studies designed to determine the potential benefit of primary thromboprophylaxis.

Cardiotoxicity of molecularly targeted agents

Cardiac toxicity of molecularly targeted cancer agents is increasingly recognized as a significant side effect of chemotherapy. These new potent therapies may not only affect the survival of cancer cells, but have the potential to adversely impact normal cardiac and vascular function. Unraveling the mechanisms by which these therapies affect the heart and vasculature is crucial for improving drug design and finding alternative therapies to protect patients predisposed to cardiovascular disease. In this review, we summarize the classification and side effects of currently approved molecularly targeted chemotherapeutics.

Thrombotic events after starting exogenous testosterone in men with previously undiagnosed familial thrombophilia

Our specific aim was to describe thrombosis (osteonecrosis of the hips, pulmonary embolism, and amaurosis fugax) after exogenous testosterone was given to men with no antecedent thrombosis and previously undiagnosed familial thrombophilia. After starting testosterone patch or gel, 50 mg/day or intramuscular testosterone 400 mg IM/month, 2 men developed bilateral hip osteonecrosis 5 and 6 months later, and 3 developed pulmonary embolism 3, 7, and 17 months later. One man developed amaurosis fugax 18 months after starting testosterone gel 50 mg/day. Of these 6 men, 5 were found to have previously undiagnosed factor V Leiden heterozygosity, 1 of whom had ancillary MTHFR C677T homozygosity, and 2 with ancillary MTHFR C677T-A1298C compound heterozygosity. One man had high factor VIII (195%), factor XI (179%), and homocysteine (29.3 umol/L). Thrombotic events after starting testosterone therapy are associated with familial thrombophilia. We speculate that when exogenous testosterone is aromatized to E2, and E2-induced thrombophilia is superimposed on familial thrombophilia, thrombosis occurs. Men sustaining thrombotic events on testosterone therapy should be screened for the factor V Leiden mutation and other familial and acquired thrombophilias.

Factor V Leiden and inflammatory bowel disease: a systematic review and meta-analysis

BACKGROUND

Recent studies proved that inflammatory bowel disease (IBD) patients had a higher risk of thromboembolism and a Factor V Leiden mutation that prevents the efficient inactivation of factor V, which leads to thromboembolism and thus contributes to a high potential risk of IBD. However, the relationship between Factor V Leiden mutation and IBD remains controversial.

METHODS

We conducted a systematic review with meta-analysis of studies assessing the association of Factor V Leiden mutation with the risk of IBD in humans. We extracted the number of IBD and control subjects with or without Factor V Leiden mutation from each study and conducted this analysis using a fixed-effects model.

RESULTS

Nineteen studies met the inclusion criteria and were included in the meta-analysis. No significant heterogeneity was found in results across the 19 studies (I (2) = 18.8%, P = 0.23), which showed a slight but not significant increase in the risk of IBD with Factor V Leiden mutation in the general population (summary odds ratio [OR] 1.13, 95% confidence interval [CI] 0.87-1.46). Taking into account ethnic differences, further study exhibited a slight but not significant increase in risk of IBD with Factor V Leiden mutation in Europeans (summary OR 1.20, 95% CI 0.88-1.64). However, Factor V Leiden mutation was significantly associated with a higher risk of thromboembolism in IBD patients (summary OR 5.30, 95% CI 2.25-12.48). No publication bias was found in this study.

CONCLUSIONS

This meta-analysis indicated that although Factor V Leiden mutation was not significantly associated with the risk of IBD, it was significantly associated with a higher risk of thromboembolism in IBD patients.

Tamoxifen promotes superoxide production in platelets by activation of PI3-kinase and NADPH oxidase pathways

BACKGROUND

Tamoxifen is a selective estrogen receptor antagonist that is widely used for treatment and prevention of breast cancer. However, tamoxifen use can lead to an increased incidence of thrombotic events. The reason for this adverse event remains unknown. Previous studies showed that tamoxifen and its active metabolite Z-4-hydroxytamoxifen rapidly increased intracellular free calcium ([Ca(2+)](i)) in human platelets by a non-genomic mechanism that involved the activation of phospholipase C. Platelets play a pivotal role in thrombosis and Ca(2+) elevation is a central event in platelet activation. Therefore the mechanism by which tamoxifen activated Ca(2+) entry into platelets was investigated.

METHODS

[Ca(2+)](i) was measured using the fluorescent indicator fura-2 and reactive oxygen species were measured using lucigenin in isolated human platelets.

RESULTS

Tamoxifen analogs E-4-hydroxytamoxifen, with weak activity at the nuclear estrogen receptor and Z-4-hydroxytamoxifen, with strong activity at nuclear estrogen receptor, were equally active at increasing [Ca(2+)](i) and synergizing with ADP and thrombin to increase [Ca(2+)](i) in platelets. This result suggests that the effects of tamoxifen and E- and Z-4-hydroxytamoxifen to increase [Ca(2+)](i) are not mediated by the classical genomic estrogen receptor. The effects of tamoxifen to increase [Ca(2+)](i) were strongly inhibited by apocynin and apocynin dimer. This suggests that tamoxifen activates NADPH oxidase which leads to superoxide generation and in turn caused an increase in [Ca(2+)](i). Free radical scavengers TEMPO and TEMPOL also inhibited tamoxifen-induced [Ca(2+)](i) elevation. Inhibition of phosphoinositide-3-kinase (PI3-kinase), an upstream effector of NADPH oxidase with wortmannin and LY-294,002 also caused substantial inhibition of tamoxifen-induced elevation of [Ca(2+)](i).

CONCLUSION

Tamoxifen increases [Ca(2+)](i) in human platelets by a non-genomic mechanism. Tamoxifen activates phospholipase Cγ as well as PI3-kinase and NADPH oxidase pathway to generate superoxide which causes the release of Ca(2+) from the endoplasmic reticulum, and promotes Ca(2+) influx into the platelets.

Toxicity of adjuvant endocrine therapy in postmenopausal breast cancer patients: a systematic review and meta-analysis

BACKGROUND

Aromatase inhibitors are associated with consistent improvements in disease-free survival but not in overall survival. We conducted a literature-based meta-analysis of randomized trials to examine whether the relative toxicity of aromatase inhibitors compared with tamoxifen may explain this finding.

METHODS

We conducted a systematic review to identify randomized controlled trials that compared aromatase inhibitors and tamoxifen as primary adjuvant endocrine therapy in postmenopausal women by searching MEDLINE, EMBASE, and databases of the American Society of Clinical Oncology and San Antonio Breast Cancer Symposium. Odds ratios (ORs), 95% confidence intervals (CIs), absolute risks, and the number needed to harm associated with one adverse event were computed for prespecified serious adverse events including cardiovascular disease, cerebrovascular disease, bone fractures, thromboembolic events, endometrial carcinoma and other second cancers not including new breast cancer. All statistical tests were two-sided.

RESULTS

Seven trials enrolling 30,023 patients met the inclusion criteria. Longer duration of aromatase inhibitor use was associated with increased odds of developing cardiovascular disease (OR = 1.26, 95% CI = 1.10 to 1.43, P < .001; number needed to harm = 132) and bone fractures (OR = 1.47, 95% CI = 1.34 to 1.61, P < .001; number needed to harm = 46), but a decreased odds of venous thrombosis (OR = 0.55, 95% CI = 0.46 to 0.64, P < .001; number needed to harm = 79) and endometrial carcinoma (OR = 0.34, 95% CI = 0.22 to 0.53, P < .001; number needed to harm = 258). Five years of aromatase inhibitors was associated with a non-statistically significant increased odds of death without recurrence compared with 5 years of tamoxifen alone or tamoxifen for 2-3 years followed by an aromatase inhibitor for 2-3 years (OR = 1.11, 95% CI = 0.98 to 1.26, P = .09).

CONCLUSIONS

The cumulative toxicity of aromatase inhibitors when used as up-front treatment may explain the lack of overall survival benefit despite improvements in disease-free survival. Switching from tamoxifen to aromatase inhibitors reduces this toxicity and is likely the best balance between efficacy and toxicity.