BACKGROUNDAmbulatory patients receiving systemic cancer therapy are at varying risk for venous thromboembolism. However, the benefit of thromboprophylaxis in these patients is uncertain. METHODSIn this double-blind, randomized trial involving high-risk ambulatory patients with cancer (Khorana score of ≥2, on a scale from 0 to 6, with higher scores indicating a higher risk of venous thromboembolism), we randomly assigned patients without deep-vein thrombosis at screening to receive rivaroxaban (at a dose of 10 mg) or placebo daily for up to 180 days, with screening every 8 weeks. The primary efficacy end point was a composite of objectively confirmed proximal deep-vein thrombosis in a lower limb, pulmonary embolism, symptomatic deepvein thrombosis in an upper limb or distal deep-vein thrombosis in a lower limb, and death from venous thromboembolism and was assessed up to day 180. In a prespecified supportive analysis involving the same population, the same end point was assessed during the intervention period (first receipt of trial agent to last dose plus 2 days). The primary safety end point was major bleeding. RESULTSOf 1080 enrolled patients, 49 (4.5%) had thrombosis at screening and did not undergo randomization. Of the 841 patients who underwent randomization, the primary end point occurred in 25 of 420 patients (6.0%) in the rivaroxaban group and in 37 of 421 (8.8%) in the placebo group (hazard ratio, 0.66; 95% confidence interval [CI], 0.40 to 1.09; P = 0.10) in the period up to day 180. In the prespecified intervention-period analysis, the primary end point occurred in 11 patients (2.6%) in the rivaroxaban group and in 27 (6.4%) in the placebo group (hazard ratio, 0.40; 95% CI, 0.20 to 0.80). Major bleeding occurred in 8 of 405 patients (2.0%) in the rivaroxaban group and in 4 of 404 (1.0%) in the placebo group (hazard ratio, 1.96; 95% CI, 0.59 to 6.49). CONCLUSIONSIn high-risk ambulatory patients with cancer, treatment with rivaroxaban did not result in a significantly lower incidence of venous thromboembolism or death due to venous thromboembolism in the 180-day trial period. During the intervention period, rivaroxaban led to a substantially lower incidence of such events, with a low incidence of major bleeding. (Funded by Janssen and others; CASSINI ClinicalTrials .gov number, NCT02555878.

Summary.  Background: Guidelines addressing the management of venous thromboembolism (VTE) in cancer patients are heterogeneous and their implementation has been suboptimal worldwide. Objectives: To establish a common international consensus addressing practical, clinically relevant questions in this setting. Methods: An international consensus working group of experts was set up to develop guidelines according to an evidence‐based medicine approach, using the GRADE system. Results: For the initial treatment of established VTE: low‐molecular‐weight heparin (LMWH) is recommended [1B]; fondaparinux and unfractionated heparin (UFH) can be also used [2D]; thrombolysis may only be considered on a case‐by‐case basis [Best clinical practice (Guidance)]; vena cava filters (VCF) may be considered if contraindication to anticoagulation or pulmonary embolism recurrence under optimal anticoagulation; periodic reassessment of contraindications to anticoagulation is recommended and anticoagulation should be resumed when safe; VCF are not recommended for primary VTE prophylaxis in cancer patients [Guidance]. For the early maintenance (10 days to 3 months) and long‐term (beyond 3 months) treatment of established VTE, LMWH for a minimum of 3 months is preferred over vitamin K antagonists (VKA) [1A]; idraparinux is not recommended [2C]; after 3–6 months, LMWH or VKA continuation should be based on individual evaluation of the benefit‐risk ratio, tolerability, patient preference and cancer activity [Guidance]. For the treatment of VTE recurrence in cancer patients under anticoagulation, three options can be considered: (i) switch from VKA to LMWH when treated with VKA; (ii) increase in LMWH dose when treated with LMWH, and (iii) VCF insertion [Guidance]. For the prophylaxis of postoperative VTE in surgical cancer patients, use of LMWH o.d. or low dose of UFH t.i.d. is recommended; pharmacological prophylaxis should be started 12–2 h preoperatively and continued for at least 7–10 days; there are no data allowing conclusion that one type of LMWH is superior to another [1A]; there is no evidence to support fondaparinux as an alternative to LMWH [2C]; use of the highest prophylactic dose of LMWH is recommended [1A]; extended prophylaxis (4 weeks) after major laparotomy may be indicated in cancer patients with a high risk of VTE and low risk of bleeding [2B]; the use of LMWH for VTE prevention in cancer patients undergoing laparoscopic surgery may be recommended as for laparotomy [Guidance]; mechanical methods are not recommended as monotherapy except when pharmacological methods are contraindicated [2C]. For the prophylaxis of VTE in hospitalized medical patients with cancer and reduced mobility, we recommend prophylaxis with LMWH, UFH or fondaparinux [1B]; for children and adults with acute lymphocytic leukemia treated with l‐asparaginase, depending on local policy and patient characteristics, prophylaxis may be considered in some patients [Guidance]; in patients receiving chemotherapy, prophylaxis is not recommended routinely [1B]; p...

IMPORTANCE Cerebral venous sinus thrombosis (CVST) with thrombocytopenia, a rare and serious condition, has been described in Europe following receipt of the ChAdOx1 nCoV-19 vaccine (Oxford/AstraZeneca), which uses a chimpanzee adenoviral vector. A mechanism similar to autoimmune heparin-induced thrombocytopenia (HIT) has been proposed. In the US, the Ad26.COV2.S COVID-19 vaccine (Janssen/Johnson & Johnson), which uses a human adenoviral vector, received Emergency Use Authorization (EUA) on February 27, 2021. By April 12, 2021, approximately 7 million Ad26.COV2.S vaccine doses had been given in the US, and 6 cases of CVST with thrombocytopenia had been identified among the recipients, resulting in a temporary national pause in vaccination with this product on April 13, 2021. OBJECTIVE To describe reports of CVST with thrombocytopenia following Ad26.COV2.S vaccine receipt. DESIGN, SETTING, AND PARTICIPANTS Case series of 12 US patients with CVST and thrombocytopenia following use of Ad26.COV2.S vaccine under EUA reported to the Vaccine Adverse Event Reporting System (VAERS) from March 2 to April 21, 2021 (with follow-up reported through April 21, 2021). EXPOSURES Receipt of Ad26.COV2.S vaccine. MAIN OUTCOMES AND MEASURES Clinical course, imaging, laboratory tests, and outcomes after CVST diagnosis obtained from VAERS reports, medical record review, and discussion with clinicians.RESULTS Patients' ages ranged from 18 to younger than 60 years; all were White women, reported from 11 states. Seven patients had at least 1 CVST risk factor, including obesity (n = 6), hypothyroidism (n = 1), and oral contraceptive use (n = 1); none had documented prior heparin exposure. Time from Ad26.COV2.S vaccination to symptom onset ranged from 6 to 15 days. Eleven patients initially presented with headache; 1 patient initially presented with back pain and later developed headache. Of the 12 patients with CVST, 7 also had intracerebral hemorrhage; 8 had non-CVST thromboses. After diagnosis of CVST, 6 patients initially received heparin treatment. Platelet nadir ranged from 9 ×10 3 /μL to 127 ×10 3 /μL. All 11 patients tested for the heparin-platelet factor 4 HIT antibody by enzyme-linked immunosorbent assay (ELISA) screening had positive results. All patients were hospitalized (10 in an intensive care unit [ICU]). As of April 21, 2021, outcomes were death (n = 3), continued ICU care (n = 3), continued non-ICU hospitalization (n = 2), and discharged home (n = 4). CONCLUSIONS AND RELEVANCEThe initial 12 US cases of CVST with thrombocytopenia after Ad26.COV2.S vaccination represent serious events. This case series may inform clinical guidance as Ad26.COV2.S vaccination resumes in the US as well as investigations into the potential relationship between Ad26.COV2.S vaccine and CVST with thrombocytopenia.

LEARNING OBJECTIVES1. Enumerate procoagulant factors present in malignancy and the risk for thromboembolic events.2. Describe the morbidity associated with nonbacterial thrombotic endocarditis.3. List the recommended evaluations and treatments for nonbacterial thrombotic endocarditis.Access and take the CME test online and receive 1 AMA PRA Category 1 Credit ™ at CME.TheOncologist.com CME CME ABSTRACTThrombophilia is a well-described consequence of cancer and its treatment. The pathogenesis of this phenomenon is complex and multifactorial. Nonbacterial thrombotic endocarditis (NBTE) is a serious and potentially underdiagnosed manifestation of this prothrombotic state that can cause substantial morbidity in affected patients, most notably recurrent or multiple ischemic cerebrovascular strokes. Diagnosis of NBTE requires a high degree of clinical suspicion as well as the judicious use of two-dimensional echocardiography to document the presence of valvular thrombi. In the absence of contraindications to therapy, treatment consists of systemic anticoagulation, which may ameliorate symptoms and prevent further thromboembolic episodes, as well as control of the underlying malignancy whenever possible. The Oncologist 2007;12:518 -523 Disclosure of potential conflicts of interest is found at the end of this article.

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines ®) are a statement of consensus of the authors regarding their views of currently accepted approaches to treatment. The NCCN Guidelines ® Insights highlight important changes in the NCCN Guidelines ® recommendations from previous versions. Colored markings in the algorithm show changes and the discussion aims to further understanding of these changes by summarizing salient portions of the panel's discussion, including the literature reviewed. The NCCN Guidelines Insights do not represent the full NCCN Guidelines; further, the National Comprehensive Cancer Network® (NCCN ®) makes no representation or warranties of any kind regarding the content, use, or application of the NCCN Guidelines and NCCN Guidelines Insights and disclaims any responsibility for their applications or use in any way. The full and most current version of these NCCN Guidelines is available at NCCN.org.

Summary.  Background: Although long‐term indwelling central venous catheters (CVCs) may lead to pulmonary embolism (PE) and loss of the CVC, there is lack of consensus on management of CVC‐related thrombosis (CRT) in cancer patients and heterogeneity in clinical practices worldwide. Objectives: To establish common international Good Clinical Practices Guidelines (GCPG) for the management of CRT in cancer patients. Methods: An international working group of experts was set up to develop GCPG according to an evidence‐based medicine approach, using the GRADE system. Results: For the treatment of established CRT in cancer patients, we found no prospective randomized studies, two non‐randomized prospective studies and one retrospective study examining the efficacy and safety of low‐molecular‐weight heparin (LMWH) plus vitamin K antagonists (VKAs). One retrospective study evaluated the benefit of CVC removal and two small retrospective studies were on thrombolytic drugs. For the treatment of symptomatic CRT, anticoagulant treatment (AC) is recommended for a minimum of 3 months; in this setting, LMWHs are suggested. VKAs can also be used, in the absence of direct comparisons of these two types of anticoagulants in this setting [Guidance]. The CVC can be kept in place if it is functional, well‐positioned and non‐infected and there is good resolution under close surveillance; whether the CVC is kept or removed, no standard approach in terms of AC duration has been established [Guidance]. For the prophylaxis of CRT in cancer patients, we found six randomized studies investigating the efficacy and safety of VKA vs. placebo or no treatment, one on the efficacy and safety of unfractionnated heparin, six on the value of LMWH, one double‐blind randomized and one non randomized study on thrombolytic drugs and six meta‐analyses of AC and CVC thromboprophylaxis. Type of catheter (open‐ended like the Hickman® catheter vs. closed‐ended catheter with a valve like the Groshong® catheter), its position (above, below or at the junction of the superior vena cava and the right atrium) and method of placement may influence the onset of CRT on the basis of six retrospective trials, four prospective non‐randomized trials, three randomized trials and one meta‐analysis. In light of these data: use of AC for routine prophylaxis of CRT is not recommended [1A]; a CVC should be inserted on the right side, in the jugular vein, and distal extremity of the CVC should be located at the junction of the superior vena cava and the right atrium [1A]. Conclusion: Dissemination and implementation of these international GCPG for the prevention and treatment of CRT in cancer patients at each national level is a major public health priority, needing worldwide collaboration.

Thrombophilias are hereditary and/or acquired conditions that predispose patients to thrombosis. Testing for thrombophilia is commonly performed in patients with venous thrombosis and their relatives; however such testing usually does not provide information that impacts management and may result in harm. This manuscript, initiated by the Anticoagulation Forum, provides clinical guidance for thrombophilia testing in five clinical situations: following 1) provoked venous thromboembolism, 2) unprovoked venous thromboembolism; 3) in relatives of patients with thrombosis, 4) in female relatives of patients with thrombosis considering estrogen use; and 5) in female relatives of patients with thrombosis who are considering pregnancy. Additionally, guidance is provided regarding the timing of thrombophilia testing. The role of thrombophilia testing in arterial thrombosis and for evaluation of recurrent pregnancy loss is not addressed. Statements are based on existing guidelines and consensus expert opinion where guidelines are lacking. We recommend that thrombophilia testing not be performed in most situations. When performed, it should be used in a highly selective manner, and only in circumstances where the information obtained will influence a decision important to the patient, and outweigh the potential risks of testing. Testing should not be performed during acute thrombosis or during the initial (3-month) period of anticoagulation.

This guidance document focuses on the diagnosis and treatment of venous thromboembolism (VTE). Efficient, cost effective diagnosis of VTE is facilitated by combining medical history and physical examination with pre-test probability models, D dimer testing and selective use of confirmatory imaging. Clinical prediction rules, biomarkers and imaging can be used to tailor therapy to disease severity. Anticoagulation options for acute VTE include unfractionated heparin, low molecular weight heparin, fondaparinux and the direct oral anticoagulants (DOACs). DOACs are as effective as conventional therapy with LMWH and vitamin K antagonists. Thrombolytic therapy is reserved for massive pulmonary embolism (PE) or extensive deep vein thrombosis (DVT). Inferior vena cava filters are reserved for patients with acute VTE and contraindications to anticoagulation. Retrievable filters are strongly preferred. The possibility of thoracic outlet syndrome and May-Thurner syndrome should be considered in patients with subclavian/axillary and left common iliac vein DVT, respectively in absence of identifiable triggers. The optimal duration of therapy is dictated by the presence of modifiable thrombotic risk factors. Long term anticoagulation should be considered in patients with unprovoked VTE as well as persistent prothrombotic risk factors such as cancer. Short-term therapy is sufficient for most patients with VTE associated with transient situational triggers such as major surgery. Biomarkers such as D dimer and risk assessment models such the Vienna risk prediction model offer the potential to customize VTE therapy for the individual patient. Insufficient data exist to support the integration of bleeding risk models into duration of therapy planning.