Expression of Tissue Factor in Epithelial Ovarian Carcinoma Is Involved in the Development of Venous Thromboembolism

Gynecological Cancer and Venous Thromboembolism: A Narrative Review to Increase Awareness and Improve Risk Assessment and Prevention

The prevention and appropriate management of venous thromboembolism in cancer patients is of paramount importance. However, the literature data report an underestimation of this major problem in patients with gynecological cancers, with an inconsistent venous thromboembolism risk assessment and prophylaxis in this patient setting. This narrative review provides a comprehensive overview of the available evidence regarding the management of venous thromboembolism in cancer patients, focusing on the specific context of gynecological tumors, exploring the literature discussing risk factors, risk assessment, and pharmacological prophylaxis. We found that the current understanding and management of venous thromboembolism in gynecological malignancy is largely based on studies on solid cancers in general. Hence, further, larger, and well-designed research in this area is needed.

Cancer-Associated Thrombosis: Epidemiology, Pathophysiological Mechanisms, Treatment, and Risk Assessment

Cancer patients represent a growing population with drastically difficult care and a lowered quality of life, especially due to the heightened risk of vast complications. Thus, it is well established so far that one of the most prominent complications in individuals with cancer is venous thromboembolism. Since there are various improved methods for screening and diagnosing cancer and its complications, the incidence of cancer-associated thrombosis has been on the rise in recent years. Therefore, the high mortality and morbidity rates among these patients are not a surprise. Consequently, there is an excruciating need for understanding the mechanisms behind this complex process, as well as the imperative for adequate analysis and application of the most suitable steps for cancer-associated thrombosis prevention. There are various and numerous mechanisms offering potential answers to cancer-associated thrombosis, some of which have already been elucidated in various preclinical and clinical scenarios, yet further and more elaborate studies are crucial to understanding and preventing this complex and harsh clinical entity. This article elaborates on the growing incidence, mortality, morbidity, and risk factors of cancer-associated thrombosis while emphasizing the pathophysiological mechanisms in the light of various types of cancer in patients and summarizes the most novel therapy and prevention guidelines recommendations.

Clear cell carcinoma of the ovary and venous thromboembolism: a systematic review and meta-analysis

OBJECTIVES

As the second most common subtype of Epithelial ovarian cancers (EOCs), ovarian clear cell carcinoma (OCCC) is associated with a high rate of cancer-associated thrombosis. Previous studies revealed the wide range prevalence (6-42%) of venous thromboembolism (VTE) among OCCC patients. This study aimed to determine the prevalence of VTE among OCCC patients as well as factors affecting it.

METHODS

PubMed, Scopus, Embase, and Cochrane Library databases were searched up to December 12th, 2022. Studies reporting venous thromboembolic events in women with clear cell carcinoma of the ovary were included. Demographic data, clinical, and paraclinical features of the patients were independently extracted by two reviewers.

RESULTS

Out of the 2254 records, 43 studies were processed for final review. The qualified studies involved 573 VTE cases among 2965 patients with OCCC. The pooled prevalence of VTE among OCCC patients was 21.32% (95%CI=(17.38-25.87)). Most VTE events were reported in Japanese women (26.15%), followed by Americans (24.41%) and UK (21.57%), and Chinese (13.61%) women. VTE was more common in patients with advanced stages (37.79%) compared to those with early stages of the disease (16.54%).

CONCLUSIONS

Ovarian clear cell carcinoma is associated with a high rate of cancer-associated thrombosis. VTE events in OCCC patients were higher in advanced stages and Japanese women.

Crosstalk of Immune Cells and Platelets in an Ovarian Cancer Microenvironment and Their Prognostic Significance

Ovarian cancer (OC) is one of the deadliest gynecological cancers, largely due to the fast development of metastasis and drug resistance. The immune system is a critical component of the OC tumor microenvironment (TME) and immune cells such as T cells, NK cells, and dendritic cells (DC) play a key role in anti-tumor immunity. However, OC tumor cells are well known for evading immune surveillance by modulating the immune response through various mechanisms. Recruiting immune-suppressive cells such as regulatory T cells (Treg cells), macrophages, or myeloid-derived suppressor cells (MDSC) inhibit the anti-tumor immune response and promote the development and progression of OC. Platelets are also involved in immune evasion by interaction with tumor cells or through the secretion of a variety of growth factors and cytokines to promote tumor growth and angiogenesis. In this review, we discuss the role and contribution of immune cells and platelets in TME. Furthermore, we discuss their potential prognostic significance to help in the early detection of OC and to predict disease outcome.

Tissue factor as a novel diagnostic target for early detection of ovarian cancer using ultrasound microbubbles

INTRODUCTION

Ovarian cancer (OC) is the deadliest gynecologic malignancy, with an overall 5-year survival rate of less than 30%. The existing paradigm for OC detection involves a serum marker, CA125, and ultrasound examination, neither of which is sufficiently specific for OC. This study addresses this deficiency through the use of a targeted ultrasound microbubble directed against tissue factor (TF).

METHODS

TF expression was examined in both OC cell lines and patient-derived tumor samples via western blotting and IHC. In vivo microbubble ultrasound imaging was analyzed using high grade serous ovarian carcinoma orthotopic mouse models.

RESULTS

While TF expression has previously been described on angiogenic, tumor-associated vascular endothelial cells (VECs) of several tumor types, this is first study to show TF expression on both murine and patient-derived ovarian tumor-associated VECs. Biotinylated anti-TF antibody was conjugated to streptavidin-coated microbubbles and in vitro binding assays were performed to assess the binding efficacy of these agents. TF-targeted microbubbles successfully bound to TF-expressing OC cells, as well as an in vitro model of angiogenic endothelium. In vivo, these microbubbles bound to the tumor-associated VECs of a clinically relevant orthotopic OC mouse model.

CONCLUSION

Development of a TF-targeted microbubble capable of successfully detecting ovarian tumor neovasculature could have significant implications towards increasing the number of early-stage OC diagnoses. This preclinical study shows potential for translation to clinical use, which could ultimately help increase the number of early OC detections and decrease the mortality associated with this disease.

The role of tissue factor pathway inhibitor 2 in the coagulation and fibrinolysis system

AIM

Tissue factor (TF), the primary initiator of the extrinsic coagulation pathway, contributes to the generation of a hypercoagulable and prothrombotic state in cancer patients. TF pathway inhibitor (TFPI) is a major inhibitor of TF-mediated coagulation pathway. The two proteins, TFPI1 and TFPI2, are encoded by separate genes. Indeed, various cancer patients with venous thromboembolism (VTE) had significantly lower TFPI1 levels than those without VTE. In contrast, serum TFPI2 level was found to increase in ovarian cancer patients with VTE. It remains unclear why TFPI2, unlike TFPI1, is elevated in ovarian cancer patients with VTE. The aim of this review is to explore the pathophysiological role of TFPI2 on the coagulation and fibrinolysis system.

METHODS

A literature search was performed from inception to April 30, 2022 in the PubMed and Google Scholar databases.

RESULTS

TFPI1 and TFPI2 are homologs with different protease inhibitory activities in the coagulation and fibrinolysis system. TFPI1 inhibits TF/factor VIIa (FVIIa) catalyzed factor X (FX) activation. On the other hand, TFPI2 is unlikely to affect TF-initiated thrombin generation, but it has strong inhibitory activity against plasmin. Plasmin is involved in fibrin degradation, clot lysis, and inactivation of several coagulation factors (such as FV, FVIII, FIX, and FX). TFPI2 may increase the risk of VTE by inhibiting plasmin-dependent fibrinolysis.

CONCLUSION

TFPI1 and TFPI2 may have different key functions in regulating the coagulation and fibrinolytic systems.

Revisiting antibody-drug conjugates and their predictive biomarkers in platinum-resistant ovarian cancer

Until to date, platinum derived drugs are still the backbone of treating ovarian cancer (OC). Most patients treated with platinum-based chemotherapy develop resistance during the course of their management. The treatment of platinum-resistant ovarian cancer (PROC) is challenging. Few therapeutic options are available for patients with this aggressive disease. Besides, there are liminal advances regarding new anticancer drugs as well as validated predictive biomarkers of clinical outcomes in this setting. The enrollment of PROC patients in interventional studies is limited as compared to newly launched clinical trials for platinum-sensitive OC. Enthusiastically, the emergence of antibody-drug conjugates (ADCs) has provided promising findings for further clinical development in PROC. ADCs have the advantage to selectively deliver cytotoxic drugs to cancer cells expressing several of antigens using specific monoclonal antibodies based on the concept of immune bioconjugation. This innovative class of therapeutics showed encouraging early signs of clinical efficacy in PROC particularly mirvetuximab soravtansine that has been successfully introduced into three randomized and controlled phase III studies. In this review, the evidence from clinical trials supporting the development of ADCs targeting folate receptor alpha, sodium-dependent phosphate transporter 2B, dipeptidase 3, mesothelin, mucin 16, and tissue factor using various cytotoxic payloads in PROC is reviewed.

Toward an understanding of tissue factor pathway inhibitor-2 as a novel serodiagnostic marker for clear cell carcinoma of the ovary

AIMS

Tissue factor pathway inhibitor (TFPI)-2 has recently emerged as a serodiagnostic marker for patients with epithelial ovarian cancer (EOC), especially clear cell carcinoma (CCC). This review discusses the biological properties of TFPI-2 and why serum levels are elevated in CCC patients.

METHODS

A comprehensive literature search was conducted in PubMed up until March, 2021.

RESULTS

TFPI-2 is a Kunitz-type protease inhibitor and negatively regulates the enzymatic activities, such as plasmin. TFPI-2 has been characterized as a tumor suppressor gene and was frequently downregulated through promoter hypermethylation in various human cancers. In contrast, TFPI-2 was overexpressed only in CCC. TFPI-2 may be involved in the pathophysiology of CCC, possibly through regulation of coagulation system, stabilization of extracellular matrix (ECM), and induction of intracellular signal transduction. TFPI-2 suppresses tissue factor-induced hypercoagulation in a hypoxic environment. TFPI-2, secreted by CCC cells, platelets, and adjacent vascular endothelial cells, may suppress tumor growth and invasion through ECM remodeling. Nuclear TFPI-2 may suppress matrix metalloproteinase production via transcription factors and modulate caspase-mediated cell apoptosis. CCC cells may upregulate the TFPI-2 expression to adapt to survival in the demanding environment. TFPI-2 is secreted by CCC cells and enters the systemic circulation, resulting in elevated blood levels.

DISCUSSION

Serum TFPI-2 reflects the overexpression of TFPI-2 in CCC tissues and is a potential serodiagnostic marker. Further research is needed to explore the expression, clinical significance, biological function, and potential mechanism of TFPI-2 in CCC.

Updates of Pathogenesis, Diagnostic and Therapeutic Perspectives for Ovarian Clear Cell Carcinoma

Ovarian clear cell carcinoma (OCCC) is a special pathological type of epithelial ovarian carcinoma (EOC) and has a high prevalence in Asia without specific molecular subtype classification. Endometriosis is a recognized precancerous lesion that carries 3-fold increased risk of OCCC. Ovarian endometrioid carcinoma, which also originates from endometriosis, shares several features with OCCC, including platinum resistance and younger age at diagnosis. Patients with OCCC have about a 2.5 to 4 times greater risk of having a venous thromboembolism (VTE) compared with other EOC, and OCCC tends to metastasize through lymphatic vesicular and peritoneal spread as opposed to hematogenous metastasis. There is only mild elevation of the conventional biomarker CA125. Staging surgery or optimal cytoreduction combined with chemotherapy is a common therapeutic strategy for OCCC. However, platinum resistance commonly portends a poor prognosis, so novel treatments are urgently needed. Targeted therapy and immunotherapy are currently being studied, including PARP, EZH2, and ATR inhibitors combined with the synthetic lethality of ARID1A-dificiency, and MAPK/PI3K/HER2, VEGF/bFGF/PDGF, HNF1β, and PD-1/PD-L1 inhibitors. Advanced stage, suboptimal cytoreduction, platinum resistance, lymph node metastasis, and VTE are major prognostic predictors for OCCC. We focus on update pathogenesis, diagnostic methods and therapeutic approaches to provide future directions for clinical diagnosis and treatment of OCCC.

Effect of myeloperoxidase on the anticoagulant activity of low molecular weight heparin and rivaroxaban in an in vitro tumor model

BACKGROUND

Inflammation with leukocyte activation is a hallmark of cancer-associated thrombosis (CAT), and elevated leukocytes predict venous thromboembolism in cancer outpatients. In a recent trial, rivaroxaban was more efficacious than dalteparin in preventing CAT recurrence.

OBJECTIVES

In a proof-of-concept study, we aimed to provide a mechanistic basis for improved efficacy of rivaroxaban compared to low molecular weight heparin in CAT treatment.

METHODS

We studied the effects of rivaroxaban, dalteparin, and tinzaparin at peak and trough levels on tumor cell-induced procoagulant activity and platelet aggregation in the presence or absence of the cationic leukocyte-derived enzyme, myeloperoxidase (MPO). Furthermore, pro-inflammatory conditions were generated by stimulating whole blood with lipopolysaccharide (LPS) or phorbol-myristate-acetate (PMA), before measuring thrombin generation in plasma supernatants.

RESULTS

All three anticoagulants inhibited thrombin generation, fibrin clot formation, and platelet aggregation induced by the tissue factor-expressing prostate carcinoma cell line, 22Rv1. Pre-incubation with MPO partially attenuated the anticoagulant activity of dalteparin and tinzaparin, but not rivaroxaban, at trough levels. The effect of MPO did not involve the enzyme's catalytic properties, but required its structural integrity, as indicated by heat denaturation. In plasma obtained from LPS- or PMA-stimulated whole blood, elevated MPO antigen levels inversely correlated with the ability of tinzaparin to inhibit 22Rv1-induced thrombin generation.

CONCLUSIONS

Myeloperoxidase release may partially attenuate the anticoagulant activity of trough levels of dalteparin and tinzaparin in the context of paraneoplastic leukocyte activation. However, this effect is likely not sufficient to explain the improved efficacy of rivaroxaban, and possibly other oral factor Xa inhibitors, in CAT treatment.

Meta-Analysis of VTE Risk: Ovarian Cancer Patients by Stage, Histology, Cytoreduction, and Ascites at Diagnosis

Venous thromboembolisms (VTEs) have been a leading secondary cause of death among ovarian cancer patients, prompting multiple studies of risk factors. The objective of this meta-analysis is to quantify the associations between VTE and the most commonly reported risk factors among ovarian cancer patients. PubMed, Embase, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) were used to identify observational studies. Two reviewers independently abstracted data and assessed quality via the Newcastle–Ottawa tool. A random effects model was used to calculate the pooled odds ratios for VTE with each of the following exposures: advanced cancer stage, clear cell histology, serous histology, ascites at diagnosis, and complete cytoreduction. The I² and Q tests were used to evaluate heterogeneity. Twenty cohort studies with 6,324 total ovarian cancer patients, 769 of whom experienced a VTE, were included. The odds of VTE in ovarian cancer patients were higher among patients with cancer stage III/IV (versus cancer stage I/II, pooled odds ratio (OR) 2.73; 95% CI 1.84–4.06; I²= 64%), clear cell (versus nonclear cell) histology (OR 2.11; 95% CI 1.55–2.89; I² = 6%), and ascites (versus no ascites) at diagnosis (OR 2.12; 95% CI 1.51–2.96; I² = 32%). Serous (versus nonserous) histology (OR 1.26; 95% CI 0.91–1.75; I² = 42%) and complete (versus incomplete) cytoreduction (OR 1.05; 95% CI 0.27–4.11; I² = 88%) were not associated with VTE. This meta-analysis quantifies the significantly elevated odds of VTE in ovarian cancer patients with advanced stage at diagnosis, clear cell histology, and ascites at diagnosis. Further studies are needed to account for confounders and inform clinical decision-making tools.

Deep vein thrombosis and serum D-dimer after pelvic lymphadenectomy in gynecological cancer

INTRODUCTION

Venous thromboembolism prevention during the perioperative period requires comprehensive risk-level assessment. The aim of this study was to evaluate the incidence of deep vein thrombosis and to assess the cut-off levels of serum D-dimer as a screening strategy for deep vein thrombosis during the perioperative period.

METHODS

A total of 205 patients (ovarian cancer: 68, endometrial cancer: 76, cervical cancer: 61) who underwent gynecological surgery, including retroperitoneal lymph node dissection, were enrolled. We retrospectively analyzed the data on the cut-off value of D-dimer assessed using area under the receiver operating characteristic curve preoperatively, and 2 or 3 months, postoperatively. All patients underwent leg vein ultrasonography regardless of the serum D-dimer level. Furthermore, CT scans were performed to evaluate both disease status and venous thromboembolism, including pulmonary thromboembolism. Statistical analyzes were performed using the Mann-Whitney U-test (D-dimer values of each cancer), Chi-square test, Fisher's exact test (incidence of deep vein thrombosis), and one-way analysis of variance (patient characteristics).

RESULTS

A total of 205 patients (ovarian cancer: 68, endometrial cancer: 76, cervical cancer: 61) who underwent gynecological surgery, including retroperitoneal lymph node dissection, were included in the analysis. Deep vein thrombosis rates were significantly higher in patients with ovarian cancer (P<0.001). The postoperative D-dimer value was significantly higher than the preoperative value. Postoperative D-dimer values were also significantly higher in patients who received adjuvant chemotherapy (P=0.001). The cut-off value of D-dimer was 1.55 µg/mL preoperatively (sensitivity, 48.0%; specificity, 94.1%), and this value was higher postoperatively, at 1.95 µg/mL (sensitivity, 37.0%; specificity, 90.9%).

CONCLUSION

Postoperative D-dimer values are higher not only after surgery but also in patients who received adjuvant chemotherapy. The cut-off value of D-dimer at 2 or 3 months postoperatively was higher than preoperative value.

Prevalence of venous thromboembolism at pretreatment screening and associated risk factors in 2086 patients with gynecological cancer

AIM

Postoperative pulmonary embolism can be a fatal surgical complication and is thought to occur secondary to asymptomatic venous thromboembolism (VTE) that exists preoperatively in some patients. The purpose of this study was to clarify the frequency and risk factors of pretreatment VTE in gynecological cancer patients.

METHODS

This study investigated 2086 patients with gynecological cancer (cervix, n = 754; endometrium, n = 862; ovary, n = 470) who underwent initial treatment between 2004 and 2017. Pretreatment VTE screening was performed with D-dimer (DD) levels in these patients. Based on this, the associated risk factors were retrospectively analyzed.

RESULTS

Pretreatment VTE was discovered in 7.3% of patients with cervical cancer, 11.5% of those with endometrial cancer and 27.0% of those with ovarian cancer. Significant independent risk factors were: age greater than or equal to 60 years and tumor long diameter greater than or equal to 40 mm for cervical cancer; age greater than or equal to 60 years, stage III/IV advanced disease, clear cell carcinoma and tumor long diameter greater than or equal to 60 mm for endometrial cancer; and age greater than or equal to 60 years, clear cell carcinoma and massive ascites for ovarian cancer.

CONCLUSION

Pretreatment asymptomatic VTE is very frequent in gynecological cancer patients. It may be beneficial to consider measuring DD or performing venous ultrasonography in patients with the above risk factors.

Incidence and potential predictors of thromboembolic events in epithelial ovarian carcinoma patients during perioperative period

OBJECTIVE

To assess the incidence and the risk factors of venous thromboembolism (VTE) in patients with epithelial ovarian carcinoma (EOC) during the perioperative period.

METHODS

A retrospective analysis was conducted on the patients with epithelial ovarian cancer treated in our hospital, between January 2017 and July 2019, and a comprehensive review of the medical documentation was performed to collect relevant data. We then analyzed the related factors of the thrombosis in the EOC patients, using univariate and multivariate analysis to identify significant risk factors for VTE, and bootstrap resampling method was used to verify the multivariate analysis results. The ROC curve methods were conducted to evaluate the diagnostic value for the prediction of VTE.

RESULTS

We analyzed 233 cases of patients with EOC, of whom the incidence of VTE was 11.16%. According to multivariate and 5000 bootstrap samples analysis, preoperative D-dimer levels (>4.215 μg/ml, p = 0.041 and p = 0.032) and comorbid of cerebral infarction (p < 0.001 and p < 0.001) had statistical significance in predicting VTE events; bootstrap analysis also found the Alb, CA125, OCCC had statistical significance. While According to multivariate and 5000 bootstrap samples analysis, age (>50.5 years old, p = 0.019 and p = 0.002) and nonoptimal debulking surgery (p = 0.007 and p = 0.002) showed significance in predicting VTE after surgery; bootstrap analysis also found the D-dimer levels (>4.215 μg/ml) and tuberculosis had statistical significance.

CONCLUSION

More effective thromboprophylaxis and pre-test assessment is necessary for EOC patients. For prediction VTE events, D-dimer levels (>4.215 μg/ml) were the independent predictors before operation. Age and debulking surgery were the independent predictors post operation.

Preoperative plasma D-dimer level is a useful prognostic marker in ovarian cancer

A high pre-treatment plasma D-dimer level was recently identified as a poor prognostic factor in several malignancies. The aim of this study was to evaluate the prognostic significance of plasma D-dimer levels in epithelial ovarian cancer (EOC). Data of 199 patients were retrospectively analysed. The relationships between pre-treatment D-dimer levels and other clinical parameters and prognosis were evaluated. Univariate analysis identified age, pre-treatment plasma D-dimer level, massive ascites, residual tumours, pre-treatment CA125 level, histological type, and FIGO stage as predictors of overall survival. The multivariate analysis showed that a high pre-treatment plasma D-dimer level (p=.017), residual tumours (p < .001), and FIGO stage (p = .036) were independent risk factors of overall survival. Venous thromboembolism (VTE) did not influence overall survival (p=.091). High pre-treatment D-dimer levels are associated with a poor prognosis independent of VTE status in EOC patients, and might be a useful prognostic biomarker.Impact statementWhat is already known on this subject? In recent years, a high pre-treatment plasma D-dimer level has been identified as a prognostic factor in several malignancies, but only a handful of studies have assessed the role of pre-treatment plasma D-dimer levels in patients with EOC patients. Thus, the clinical significance and prognostic value of the plasma D-dimer level in EOC remain controversial, and there is also debate related to the association of the higher mortality rate among cancer patients with elevated D-dimer levels with VTE.What do the results of this study add? In our study, high pre-treatment D-dimer levels are associated with a poor prognosis independently of VTE in EOC patients.What are the implications of these findings for clinical practice and/or further research? The D-dimer level might emerge as a valuable prognostic biomarker, which will help doctors in the choice of initiating a more aggressive therapy, the combination of chemotherapy with anticoagulation therapy.

Thrombotic events induce the worse prognosis in ovarian carcinomas and frequently develop in ovarian clear cell carcinoma

BACKGROUND

This study aimed to examine the clinical significance and risk factors of thromboembolic events (TEEs) in patients with ovarian carcinoma.

METHODS

Patients with ovarian carcinoma treated at our hospital between 2000 and 2017 were identified. The risk factors of TEEs, including venous TEEs and arterial TEEs, and the association between TEEs and prognosis were investigated. Patients with TEEs were classified into two groups: those with severe TEEs, defined as patients who required urgent treatment for deep vein thrombosis, massive pulmonary embolism, acute myocardial infarction, and symptomatic cerebral infarction, and those with mild TEEs. The risk factors of severe TEEs and the association between severe TEEs and prognosis were investigated.

RESULTS

A total of 369 patients were enrolled. Among them, 53 patients (14.4%) were complicated with TEEs. Clear cell carcinoma (CCC) was a greater risk factor of TEEs than serous carcinoma (hazard ratio [HR] = 2.81, p = 0.03). In multivariate analysis for survival, TEEs were a prognostic factor of poor progression-free survival (PFS; HR = 2.90, p < 0.01) and overall survival (OS; HR = 2.89, p < 0.01). Among 53 patients with TEEs, 17 (32.1%) developed severe TEEs. CCC was strongly associated with severe TEEs (HR = 42.6, p = 0.02). Multivariate analysis for survival demonstrated that severe TEEs were a risk factor of worse PFS (HR = 4.34, p < 0.01) and OS (HR = 3.30, p = 0.03).

CONCLUSION

TEEs induced poor prognosis and was associated with CCC. A standard treatment for CCC should be included in the strategy of TEEs.

Risk factors for deep venous thrombosis in women with ovarian cancer

We aim to clarify the incidence of deep venous thrombosis (DVT) before treatment in women with ovarian cancer and identify risk factors for DVT.In this prospective study, 110 women underwent venous ultrasonography before cancer treatment and D-dimer levels were measured. We investigated factors predicting DVT by logistic regression.DVT was detected in 25 of 110 women (22.7%) and pulmonary thromboembolism was coexisted in 2 women (1.8%). A total of 21 women (84.4%) with DVT were asymptomatic. D-dimer levels in women with DVT (median, 10.9; range, <0.5-98.2 μg/mL) were significantly higher than those in women without DVT (2.0; <0.5-60.8 μg/mL; P < .01). When 10.9 μg/mL was used as a cutoff value for D-dimer levels to predict DVT, specificity, sensitivity, and positive and negative predictive values were 92.9%, 52.0%, 68.4%, and 86.8%, respectively. The multivariate analysis demonstrated that D-dimer level (odds ratio [OR], 19.7; 95% confidence interval [CI], 5.89-76.76) and clear cell histology (OR, 7.1; 95% CI, 2.12-25.67) were independent factors predicting DVT.Asymptomatic DVT occurred with great frequency before treatment in patients with ovarian cancer. High D-dimer level and clear cell pathology is associated with a higher DVT risk.