Physicians' decision about long-term thromboprophylaxis in cancer outpatients: CAT AXIS, a case vignette study on clinical practice in France

Can thromboprophylaxis build a link for cancer patients undergoing surgical and/or chemotherapy treatment? The MeTHOS cohort study

BACKGROUND

Patients with active cancer have a 4-sevenfold increased risk for venous thromboembolism (VTE) especially during systematic anticancer treatment. Simultaneously, surgery is an additional risk factor.

METHODS

The Metaxas's Hospital THromboprophylaxis program in Oncological & Surgical Patients (MeTHOS) is a prospective, phase IV, observational, non-interventional cohort study, aiming to record the thromboprophylaxis practice patterns in high-risk active cancer patients undergoing surgical and/or chemotherapy treatment.

RESULTS

We are reporting results from 291 ambulatory patients (median age: 67 years, Q1-Q3: 59-73 years, 54.6% males) who received anti-neoplastic treatment and administered thromboprophylaxis. 59.8% had cardiovascular disease (mostly hypertension), 76.6% were reported as having at least one comorbidity, while 27.5% and 15.8% accumulated two and three comorbidities, respectively. 94.9% of the patients were receiving highly thrombogenic agents such as platinum-based agents, 5-FU, immunotherapy, antiangiogenics/anti-VEGF, or erythropoietin. 26.5% of the patients were initially surgically treated. In terms of anticoagulation, all patients were treated with tinzaparin (fixed dose, 10,000 Anti-Xa IU, OD). The median anticoagulation duration was 6.2 months. Six thrombotic events were observed (2.06%, 95% CI: 0.76-4.43%): 5 were DVT, and one PE. With respect to safety, 7 bleeding events occurred (2.6%, 95% CI: 1.0-5.3%); 6 of them were minor.

CONCLUSIONS

Thromboprophylaxis with LMWH in patients with active cancer and high thrombotic burden was safe and effective. Intermediate dose of tinzaparin seems to be an appropriate agent for cancer-associated thromboprophylaxis management.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT04248348.

Oncologists' attitudes towards prophylaxis of cancer associated venous thromboembolism: A prospective, descriptive study

INTRODUCTION

Cancer-associated venous thromboembolism creates a big burden on both patients and healthcare systems. Clinical guidelines have a consensus on the initiation of prophylactic treatment for hospitalised patients, however a debate still exists for ambulatory cancer patients. Therefore, this study aimed to identify attitudes and practices of medical oncologists on cancer-associated venous thromboembolism management.

METHODS

An online survey consisting of 22 questions was developed by researchers in the view of previous studies and delivered to 100 medical oncologists registered to the national society of medical oncology by e-mail between September and October 2018. Descriptive and statistical analyses were performed using Statistical Package for Social Science (SPSS) version 23.0 (ICM Corp. Released 2015. IBM SPSS Statistics for Windows, Version 23.0. Armonk, NY: IBM Corp).

RESULTS

A total of 62 medical oncologists (75.8% male) responded to the survey (response rate of 62%). The most critical three risk factors considered for initiating prophylaxis were prior venous thromboembolism history, immobilisation and tumour/cancer type for inpatients and outpatients (χ² test, p < 0.001). The first choice of drug for prophylaxis was mostly low molecular weight heparins (n = 60, 96.8%). In the absence of contraindications, physicians initiate prophylaxis 'usually' for inpatients (n = 25, 40.3%) and outpatients (n = 5, 8.1%). However routine use of the Khorana score is not incorporated into the risk assessment process of cancer patients.

CONCLUSION

Attitudes of oncologists towards thromboprophylaxis in cancer patients are consistent with previous studies in the literature. The respondents are aware of the venous thromboembolism risk of cancer patients, however raising awareness on both cancer-associated venous thromboembolism and current guideline recommendations is needed.

Latest advances in preventing thromboembolic disease in the ambulatory oncology patient

Venous thromboembolism (VTE) is often cited as a major cause of death and morbidity in cancer patients. Even a non-lethal VTE causes distress and is commonly perceived by patients as a set-back in the cancer journey and a threat to the cancer treatment. It is also known that the risk of VTE varies between cancers (cancer-related risk factors), between patients (patient-related risk factors), and also within the cancer journey of a single patient. Risk can increase during treatments like surgery and chemotherapy and decline during remission. Neither the low molecular weight heparins nor the vitamin K analogues have gained an established role in thromboprevention guidance other than in 'the high risk' patient, who remains a rather ambiguous entity. The recently published randomised studies of rivaroxaban and apixaban in moderate- to high-risk thrombosis patients, assigned by the Khorana Risk Score, has seen the inclusion of direct oral anticoagulants (DOACs) in recent guidelines (e.g. the American Society of Clinical Oncology 2019 guidelines) for this indication. The ease of administration and the demonstrated greater patient adherence to oral agents has heightened the expectation that a practice-changing thromboprevention study in cancer patients should be realizable. However, key unmet needs that pose familiar challenges remain and as yet do not have satisfactory solutions. Anticoagulants carry risks of bleeding that are higher in the cancer population. There is therefore the challenge of sufficient risk reduction of VTE from the intervention balanced against the number of patients that may be harmed from bleeding. There is also the challenge of penetrating the risk threshold beyond which oncologists would deem thromboprevention a clinically meaningful praxis. Thus, identifying the high-risk groups of patients or targeting the length or timing of the thromboprevention to when the risks are highest are major questions that remain the subject of ongoing research. Notably all this is taking place against a backdrop of changing therapeutics for many cancers (e.g. targeted agents, checkpoint inhibitors and combinations) and their assorted impact on VTE incidence. In this review, past data for the ambulatory cancer patient are summarised, the latest evidence for the direct oral anticoagulants apixaban and rivaroxaban are analysed and the challenges of identifying the high-risk patients that have the greater chance of benefiting from thromboprophylaxis are discussed.

Predicting VTE in Cancer Patients: Candidate Biomarkers and Risk Assessment Models

Risk prediction of chemotherapy-associated venous thromboembolism (VTE) is a compelling challenge in contemporary oncology, as VTE may result in treatment delays, impaired quality of life, and increased mortality. Current guidelines do not recommend thromboprophylaxis for primary prevention, but assessment of the patient's individual risk of VTE prior to chemotherapy is generally advocated. In recent years, efforts have been devoted to building accurate predictive tools for VTE risk assessment in cancer patients. This review focuses on candidate biomarkers and prediction models currently under investigation, considering their advantages and disadvantages, and discussing their diagnostic performance and potential pitfalls.

Recent Advances in the Management of Cancer-Associated Thrombosis: New Hopes but New Challenges

Venous thromboembolism (VTE) is a common cause of morbidity and mortality in cancer patients and leads to a significant increase in health care costs. Cancer patients often suffer from multiple co-morbidities and have both a greater risk of VTE recurrence and bleeding compared to non-cancer patients. Anticoagulation is therefore challenging. For many years, long-term therapy with Low-Molecular-Weight Heparin (LMWH) was the standard of care for the management of cancer-associated VTE. Direct oral anticoagulants (DOAC), which offer the convenience of an oral administration and have a rapid onset of action, have recently been proposed as a new option in this setting. Head-to-head comparisons between DOAC and LMWHs for the treatment of established VTE are now available, and data on the efficacy and safety of these drugs for primary prophylaxis of VTE in ambulatory cancer patients receiving systemic anticancer therapy are emerging. This narrative review aims to summarize the main recent advances in the prevention and treatment of cancer-associated VTE, including recent data on the use of individualized factors to stratify the risk of VTE in each individual patient, quality-of-life in patients treated with LMWH, and the place that DOACs will likely take in the cancer-associated VTE management landscape.