Long-term treatment of cancer-associated thrombosis: the choice of the optimal anticoagulant

Cancer-associated venous thromboembolism in the direct oral anticoagulants era: Insight from the COMMAND VTE Registry-2

BACKGROUND

There is a paucity of data on real-world management strategies and clinical outcomes of cancer-associated venous thromboembolism (VTE) in the direct oral anticoagulants (DOACs) era.

OBJECTIVES

To investigate the status of cancer-associated VTE in the DOAC era.

METHODS

This multicenter, retrospective cohort study among 31 centers in Japan between 2015 and 2020 enrolled 5197 consecutive patients with acute symptomatic VTE, who were divided into 1507 patients (29 %) with active cancer and 3690 patients (71 %) without.

RESULTS

The cumulative 3-year rate of anticoagulation discontinuation was significantly higher in patients with active cancer than in those without (62.7 % vs. 59.1 %, P < 0.001). The cumulative 5-year incidence of recurrent VTE was higher in patients with active cancer than in those without (10.1 % vs. 9.1 %, P = 0.01), however, after adjusting for the confounders and competing risk of mortality, the excess risk of the active cancer group relative to the no active cancer group was no longer significant (HR: 0.95, 95 % CI: 0.73-1.24). The cumulative 5-year incidence of major bleeding was much higher in the active cancer group (20.4 % vs. 11.6 %, P < 0.001). Even after adjusting for the confounders and competing risk of mortality, the risk of the active cancer group relative to the no active cancer group remained significant (HR: 1.36, 95 % CI: 1.11-1.66).

CONCLUSIONS

The current large real-world registry revealed that the risk of major bleeding was still higher in patients with active cancer than in those without, leading to the frequent anticoagulation discontinuation, which has been still a huge challenge to overcome in the DOAC era.

Unanswered questions in cancer-associated thrombosis

Cancer-associated venous thromboembolism (VTE) is a leading cause of morbidity and mortality in patients with cancer. Treatment of cancer-associated VTE comes with a heightened risk of anticoagulant-related bleeding that differs by choice of anticoagulant as well as by patient- and disease-specific risk factors. Available data from randomized controlled trials and observational studies in cancer-associated VTE suggest that direct oral anticoagulants are effective, continuing anticoagulation beyond six months is indicated in those with active cancer and that patients who develop 'breakthrough' thrombotic events can be effectively treated. We review the evidence that addresses these key clinical questions and offer pragmatic approaches in individualizing care. While significant investigative efforts over the past decade have made impactful advances, future research is needed to better define the factors that contribute to anticoagulant-related bleeding and VTE recurrence, in order to aid clinical decision-making that improves the care of patients with cancer-associated VTE.

Estimating Bleeding Risk in Patients with Cancer-Associated Thrombosis: Evaluation of Existing Risk Scores and Development of a New Risk Score

BACKGROUND

 Bleeding risk is highly relevant for treatment decisions in cancer-associated thrombosis (CAT). Several risk scores exist, but have never been validated in patients with CAT and are not recommended for practice.

OBJECTIVES

 To compare methods of estimating clinically relevant (major and clinically relevant nonmajor) bleeding risk in patients with CAT: (1) existing risk scores for bleeding in venous thromboembolism, (2) pragmatic classification based on cancer type, and (3) new prediction model.

METHODS

 In a posthoc analysis of the Hokusai VTE Cancer study, a randomized trial comparing edoxaban with dalteparin for treatment of CAT, seven bleeding risk scores were externally validated (ACCP-VTE, HAS-BLED, Hokusai, Kuijer, Martinez, RIETE, and VTE-BLEED). The predictive performance of these scores was compared with a pragmatic classification based on cancer type (gastrointestinal; genitourinary; other) and a newly derived competing risk-adjusted prediction model based on clinical predictors for clinically relevant bleeding within 6 months after CAT diagnosis with nonbleeding-related mortality as the competing event ("CAT-BLEED").

RESULTS

 Data of 1,046 patients (149 events) were analyzed. Predictive performance of existing risk scores was poor to moderate (C-statistics: 0.50-0.57; poor calibration). Internal validation of the pragmatic classification and "CAT-BLEED" showed moderate performance (respective C-statistics: 0.61; 95% confidence interval [CI]: 0.56-0.66, and 0.63; 95% CI 0.58-0.68; good calibration).

CONCLUSION

 Existing risk scores for bleeding perform poorly after CAT. Pragmatic classification based on cancer type provides marginally better estimates of clinically relevant bleeding risk. Further improvement may be achieved with "CAT-BLEED," but this requires external validation in practice-based settings and with other DOACs and its clinical usefulness is yet to be demonstrated.

Extracellular Vesicles Reflect the Efficacy of Wheatgrass Juice Supplement in Colon Cancer Patients During Adjuvant Chemotherapy

Introduction

Colorectal cancer (CC) is the third most common type of cancer, accounting for 10% of all cancer cases. Adjuvant chemotherapy is recommended in stages II–III CC. Wheatgrass juice (WGJ) from wheat seeds has high nutritional values, may induce synergistic benefits to chemotherapy and may attenuate chemotherapy-related side effects. Extracellular vesicles (EVs) are subcellular membrane blebs. EVs include exosomes (generated in the endosome, in size <150 nm) and microvesicles (shed from the plasma cell membrane) provide information on their parental cells and play a role in intercellular communication. We aimed to elucidate the effects of chemotherapy administration with supportive treatment of WGJ on CC patients’ EVs characteristics.

Methods

EVs were isolated from the blood samples of 15 healthy controls (HCs) and 50 CC patients post-surgery, treated by chemotherapy, with or without additional daily WGJ. Blood samples were taken before, during, and at the end of chemotherapy. EVs were characterized by size, concentration, membrane antigens and cytokine content using nanoparticle-tracking analysis, western blot, flow cytometry, and protein array methods.

Results

EVs were found to be similar by size and concentration with reduced levels of exosome markers (CD81) on samples at the end of combined treatment (chemotherapy and WGJ). Higher levels of endothelial EVs, which may indicate impairment of the vascular endothelial cells during treatment, were found in CC patients treated by chemotherapy only compared to those with chemotherapy and daily WGJ. Also, EVs thrombogenicity was lower in patients added WGJ compared to patients who had only chemotherapy (levels of tissue factor p = 0.029 and endothelial protein C receptor p = 0.005). Following treatments, levels of vascular endothelial growth factor receptors (VEGFR-1) and the majority of growth-factors/pro-inflammatory cytokines were higher in EVs of patients treated by chemotherapy only than in EVs obtained from patients with the combined treatment.

Conclusion

Daily consumption of WGJ during chemotherapy may reduce vascular damage and chemotherapy-related thrombogenicity, growth factors and cytokines, as reflected by the characteristics of patient’s EVs.

Treatment of cancer-associated venous thromboembolism in the age of direct oral anticoagulants

Anticoagulation for cancer-associated venous thromboembolism (VTE) can be challenging due to complications—including bleeding and potential drug–drug interactions with chemotherapy—associated with vitamin K antagonists and inconvenience of low-molecular-weight heparin (LMWH). Direct oral anticoagulants (DOACs) could partially overcome these issues, but until recently there were no large clinical trials assessing their efficacy and safety in cancer patients. This review summarizes clinical treatment guidelines, prior clinical and real-world evidence for anticoagulant choice, recent clinical trials assessing DOACs for cancer-associated VTE (i.e. Hokusai-VTE Cancer, SELECT-D, CARAVAGGIO, and ADAM VTE), and special considerations for DOAC use. Based on established data, clinical guidelines recommend patients with cancer-associated VTE receive LMWH treatment of at least 3–6 months. Nevertheless, LMWH is underused and associated with poor compliance and persistence in these patients relative to oral anticoagulants. Clinical data supporting DOAC use in cancer patients are becoming available. In Hokusai-VTE Cancer, edoxaban was noninferior to dalteparin for the composite of recurrent VTE and major bleeding (12.8% versus 13.5%), with numerically lower recurrent VTE (7.9% versus 11.3%) and significantly higher major bleeding (6.9% versus 4.0%); only patients with gastrointestinal cancer had significantly higher risk of bleeding with edoxaban. In SELECT-D, rivaroxaban had numerically lower VTE recurrence (4% versus 11%), comparable major bleeding (6% versus 4%), and numerically higher clinically relevant nonmajor bleeding (13% versus 4%) versus dalteparin. Most bleeding events were gastrointestinal or urologic; patients with esophageal/gastroesophageal cancer had higher rates of major bleeding with rivaroxaban (36% versus 11%). For comparison of apixaban versus dalteparin, CARAVAGGIO is ongoing, and preliminary results from ADAM VTE are favorable. This review concludes that DOACs appear to be reasonable alternatives to LMWH for treatment of cancer-associated VTE. In patients with gastrointestinal cancer, DOAC use should be considered on a case-by-case basis with consideration of the relative risks and benefits.

What is the potential use of platelet-rich-plasma (PRP) in cancer treatment? A mini review

Platelet-rich-plasma (PRP) is an autologous human platelet concentrate extracted from plasma. PRP has been investigated in order to be used in many fields, with emphasis on the musculoskeletal field applied to sports injuries, as well as on other medical fields such as cardiac surgery, gynecology, pediatric surgery, urology, ophthalmology and plastic surgery. Cancer treatment is another important field where PRP should be investigated; thus, it is important validating PRP preparation protocols to be used in clinical research. Many protocols should be revised since, overall, most studies do not provide necessary information to allow them to be multiplied or replicated. The current review focuses on several topics about cancer, mainly on innovative studies about PRP use as a feasible therapeutic alternative to treat bladder cancer - a field where it could play a key role. Relevant aspects such as platelets' contribution to immune regulation and the supportive role they play in innate and adaptive immune functions are also addressed. Another important topic reviewed in the current study refers to inflammatory process regulation associated with cancer and thrombosis sites, which indicated that tumor-induced platelet activation could be used as an important therapeutic target in the future. New aspects concerning nitric oxide's ability to restrain platelet adhesion and aggregation in order to slow metastasis progress in cancer patients provide an important advantage in cancer treatment. Finally, the current review has pointed out perspectives and the main concerns about, and possibilities of, PRP use in cancer treatment.

Efficacy and safety of direct oral anticoagulants versus low-molecular-weight heparin in patients with cancer: a systematic review and meta-analysis

The efficacy and safety of direct oral anticoagulants (DOACs) versus low-molecular-weight heparin (LMWH) are still debated in the treatment of patients with cancer, and the optimal duration of therapy remains uncertain. Electronic databases (PubMed, Embase, and Cochrane Library) were searched to retrieve studies on the efficacy and safety of DOACs versus LMWH in treating patients with cancer from January 1980 to October 2018. The primary efficacy and safety endpoints were recurrent venous thromboembolism (VTE) and major bleeding. Our study included two randomized controlled trials (RCTs) and nine observational studies, together comprising 4509 patients with cancer. The pooled estimates indicated that DOACs led to a modest reduction recurrent VTE in the RCTs [RR: 0.63, 95% confidence interval (CI), 0.42-0.96, P = 0.03] and in the observational studies (RR: 0.74, 95% CI, 0.58-0.93, P = 0.011), without increasing the risk of major bleeding for observational studies (P = 0.805), but increased for RCTs (P = 0.017). The same trends were observed in the rivaroxaban subgroup. Moreover, subgroup analyses according to the treatment duration indicated that DOACs significantly reduced the incidence of recurrent VTE (P = 0.006 at 6 months; P < 0.001 at 12 months) without significant differences in major bleeding compared with LMWH at 6 or 12 months. Patients with cancer who received DOACs exhibited a significant reduction in recurrent VTE with no increased risk of major bleeding compared with LMWH. DOACs may be an alternative choice for long-term anticoagulant therapy in patients with cancer.

Treatment of Cancer-Associated Thrombosis: Beyond HOKUSAI

Direct oral anticoagulants (DOACs) represent an attractive alternative to low-molecular-weight heparins (LMWHs) for the long-term treatment of cancer-associated thrombosis (CT) since they avoid the burden of daily injections. Analyses in subgroups of cancer patients from large randomized trials suggested that DOACs were at least as effective as vitamin K antagonists, while indirect comparisons suggested that DOACs' efficacy and safety profile were comparable to those of LMWHs. In the randomized controlled HOKUSAI-VTE Cancer study, currently the only completed phase III trial on DOACs in CT patients, edoxaban was shown noninferior to dalteparin on the composite primary endpoint of time to first recurrent venous thromboembolism or major bleeding during the 12 months after randomization. Study results suggest that both agents had comparable benefit/risk ratio in patients with CT. Even though this conclusion was valid from a strict statistical viewpoint, it was potentially misleading when interpreting benefit/risk ratios. Besides the obvious heterogeneity of the study population (e.g., 23% of patients no longer had cancer) and significantly different treatment durations between arms, secondary outcomes for efficacy were in favor of edoxaban for recurrent deep-vein thrombosis but not for recurrent pulmonary embolism, and major bleeding episodes were significantly more frequent in the edoxaban group, with an excess of gastrointestinal (GI) bleeding episodes observed mainly but not only in patients with GI cancers. More research is needed regarding specific patients' profiles, cancer types, and treatment period to better clarify the respective roles of DOACs and LMWHs in CT patients.

Direct oral anticoagulants for treatment and prevention of venous thromboembolism in cancer patients

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in patients with cancer. Compared with the general population, cancer patients with VTE have higher rates of both VTE recurrence and bleeding. While low molecular weight heparin (LMWH) has been the mainstay of treatment for cancer-associated VTE for over a decade, direct oral anticoagulants (DOACs) have recently emerged as a new therapeutic option due to their ease of administration and because they do not require laboratory monitoring. Several large randomized clinical trials have been performed or are ongoing at the time of writing, comparing DOACs with LMWH in this population. Three of these trials have thus far been published and suggest that DOACs are a reasonable alternative to LMWH for management of cancer-associated VTE. Despite the advantages offered by DOACs, these agents may not be appropriate for certain patient groups owing to increased risk of bleeding, organ compromise, extremes of weight, and other issues. Finally, data are emerging suggesting that DOACs may be useful for primary thromboprophylaxis in cancer patients in conjunction with validated risk assessment scores. In this evidence-based review, data for the use of DOACs to treat cancer-associated VTE will be examined, focusing on efficacy, safety, and timing of treatment. Guidance on choosing the optimal anticoagulant for a given patient is also offered.

Cancer-Associated Thrombosis: Beyond Clinical Practice Guidelines-A Multidisciplinary (SEMI-SEOM-SETH) Expert Consensus

Despite the growing interest and improved knowledge about venous thromboembolism in cancer patients in the last years, there are still many unsolved issues. Due to the limitations of the available literature, evidence-based clinical practice guidelines are not able to give solid recommendations for challenging scenarios often present in the setting of cancer-associated thrombosis (CAT). A multidisciplinary expert panel from three scientific societies—Spanish Society of Internal Medicine (SEMI), Spanish Society of Medical Oncology (SEOM), and Spanish Society Thrombosis and Haemostasis (SETH)—agreed on 12 controversial questions regarding prevention and management of CAT, which were thoroughly reviewed to provide further guidance. The suggestions presented herein may facilitate clinical decisions in specific complex circumstances, until these can be made leaning on reliable scientific evidence.

Net Clinical Benefit of Non-vitamin K Antagonist Oral Anticoagulants for Venous Thromboembolism Prophylaxis in Patients With Cancer: A Systematic Review and Trade-Off Analysis From 9 Randomized Controlled Trials

Venous thromboembolism (VTE) is highly prevalent in patients with cancer. Non-vitamin K antagonist oral anticoagulants (NOACs), directly targeting the enzymatic activity of thrombin or factor Xa, have been shown to be as effective as and safer than traditional anticoagulation for VTE prophylaxis in no-cancer patients. However, related studies that focused on the anticoagulation in cancer patients are lacked, and almost no net clinical benefit (NCB) analyses that quantified both VTE events and bleeding events have been addressed in this fragile population. Therefore, we aim to investigate this issue using a systematic review and NCB analysis. A comprehensive search of Medline, Embase, and Cochrane Library were performed for randomized controlled trials (RCTs) that reported the VTE events and major bleeding of NOACs and traditional anticoagulants in patients with or without cancer. Odds ratios (ORs) and 95% confidence intervals (CIs) of VTE and bleeding events were calculated using a random-effects model. The primacy outcome of narrow NCB was calculated by pooling ORs of VTE and major bleeding, with a weighting of 1.0. Similarly, the broad NCB was calculated by pooling ORs of VTE and clinically relevant bleeding. Heterogeneity was assessed through I² test and Q statistic, and subgroup analyses were performed on the basis of different patients (VTE patients or acutely ill patients), comparators (vitamin-K antagonists or low-molecular-weight heparin), and follow-up duration (≤6 months or >6 months). Overall, 9 RCTs including 41,454 patients were enrolled, of which 2,902 (7%) were cancer patients, and 38,552 (93%) were no-cancer patients; 20,712 (50%) were administrated with NOACs and 20,742 (50%) were administrated with traditional anticoagulants. The use of NOACs had a superior NCB than traditional anticoagulation in both cancer patients (OR: 0.68, 95%CI: 0.50-0.85 for narrow NCB; OR: 0.76, 95%CI: 0.61–0.91 for broad NCB) and no-cancer patients (OR: 0.75, 95%CI: 0.54-0.96 for narrow NCB; OR: 0.85, 95%CI: 0.67–1.04 for broad NCB), with the estimates mainly from VTE patients receiving long-term warfarin treatment. In conclusion, NOACs may represent a better NCB property compared to traditional anticoagulants in cancer patients who need long-term anticoagulation treatment.

New Interfaces of Thyroid Hormone Actions With Blood Coagulation and Thrombosis

Substantial clinical evidence indicates hyperthyroidism enhances coagulation and increases the risk of thrombosis. In vitro and clinical evidence implicate multiple mechanisms for this risk. Genomic actions of thyroid hormone as 3,5,3′-triiodo-L-thyronine (T₃) via a nuclear thyroid hormone receptor have been implicated, but recent evidence shows that nongenomic mechanisms initiated at the receptor for L-thyroxine (T₄) on platelet integrin αvβ3 are prothrombotic. The T₄-initiated mechanisms involve platelet activation and, in addition, cellular production of cytokines and chemokines such as CX3CL1 with procoagulatory activities. These procoagulant actions of T₄ are particulary of note because within cells T4 is not seen to be functional, but to be only a prohormone for T₃. Finally, it is also possible that thyroid hormone stimulates platelet-endothelial cell interaction involved in local thrombus generation. In this brief review, we survey mechanisms by which thyroid hormone is involved in coagulation and platelet functions. It is suggested that the threshold should be lowered for considering the possibility that clinically significant clotting may complicate hyperthyroidism. The value of routine measurement of partial thromboplastin time or circulating D-dimer in patients with hyperthyroid or in patients treated with thyrotropin-suppressing dosage of T₄ requires clinical testing.

Assessment of bleeding incidences associated with rivaroxaban therapy in adults with solid tumors

PURPOSE

Report bleeding incidences associated with rivaroxaban in adult patients with solid tumor malignancies requiring anticoagulation therapy.

METHODS

This retrospective review was conducted at Indiana University Health, University Hospital and the Simon Cancer Center in Indianapolis, IN from January 2013 - February 2016. Patients were included if they had a solid tumor malignancy and prescribed rivaroxaban. Data were collected on 144 patients. Major bleeding was defined as bleeding requiring treatment (local, systemic treatment, blood cell transfusions) or hospitalization and minor bleeding was defined as bleeding not requiring treatment or hospitalization.

RESULTS

Sixty-four (44%) patients experienced bleeding while on rivaroxaban. There were six cancer types that had a higher incidence of bleeding: bladder, breast, melanoma, pancreas, prostate, and renal cell cancers; 40% (6/15) of patients with bladder cancer experienced bleeding; 54% (7/13) with breast cancer experienced bleeding; 40% (4/10) of patients with melanoma experienced bleeding; 58% (11/19) of patients with pancreatic cancer experienced bleeding; 45% (10/22) of patients with prostate cancer experienced bleeding; and 56% (5/9) of patients with renal cell carcinoma experienced bleeding. No other data collected identified increased incidence of bleeding.

CONCLUSIONS

Patients on rivaroxaban with a diagnosis of bladder, breast, melanoma, pancreas, prostate, or renal cell cancers had a higher incidence of bleeding compared to other solid tumors. Major bleeding was higher in bladder, breast, pancreas, and renal cell carcinomas, while minor bleeding was higher in patients with melanoma and prostate cancer.

The pro-inflammatory role of platelets in cancer

Thrombosis is a frequent issue in cancer patients. Tumor-induced platelet activation and coagulation does not only constitute a significant risk for thrombosis, but also contribute to tumor progression by promoting critical processes such as angiogenesis and metastasis. In addition to their role in hemostasis, platelets are increasingly recognized as regulators of inflammation. By modulating the immune system, platelets regulate several aspects of cancer-associated pathology. Platelets influence the inflammatory response in cancer by affecting the activation status of the endothelium and by recruiting leukocytes to primary and metastatic tumor sites, as well as to distant organs unaffected by tumor growth. Furthermore, platelets participate in the formation of neutrophil extracellular traps, which can promote metastasis, thrombosis, and contribute to organ failure. In this review, we discuss the role of platelets as coordinators of the immune system during malignant disease and the potential of targeting platelets to prevent cancer-associated pathology.