OC-02 Gemcitabine with or without prophylactic weight-adjusted dalteparin (WAD) in patients with advanced or metastatic pancreatic cancer (APC): a multicentre, randomised phase IIB trial (the UK FRAGEM study)

Efficacy and safety of thromboprophylaxis in cancer patients: a systematic review and meta-analysis

BACKGROUND

Thrombosis is a common complication in patients with cancer. Whether thromboprophylaxis could benefit patients with cancer is unclear. The aim of this systematic review was to determine the efficacy and safety of thromboprophylaxis in patients with cancer undergoing surgery or chemotherapy.

METHODS

We searched the Cochrane Library, EMBASE, MEDLINE, EBSCOhost, and Web of Science for studies published before May 2018 to investigate whether thromboprophylaxis measures were more effective than a placebo in patients with cancer.

RESULTS

In total, 33 trials with 11,942 patients with cancer were identified. In patients with cancer undergoing surgery, the administration of thromboprophylaxis was associated with decreasing trends in venous thromboembolism (VTE) [relative risk (RR) 0.51, 95% confidence interval (CI) 0.32-0.81] and DVT (RR 0.53, 95% CI 0.33-0.87). In patients with cancer undergoing chemotherapy, the administration of thromboprophylaxis reduced the incidences of VTE, DVT, and pulmonary embolism compared with no thromboprophylaxis (RR 0.54, 95% CI 0.40-0.73; RR 0.47, 95% CI 0.31-0.73; RR 0.51, 95% CI 0.32-0.81, respectively). The pooled results regarding major bleeding showed no significant difference between prophylaxis and no prophylaxis in either the surgical or the chemotherapy groups (RR 2.35, 95% CI 0.74-7.52, p = 0.1482, I2 = 0%; RR 1.30, 95% CI 0.93-1.83, p = 0.1274, I2 = 0%, respectively).

CONCLUSION

Thromboprophylaxis did not increase major bleeding events or the incidence of thrombocytopenia. All-cause mortality was not significantly different between those who received thromboprophylaxis and those who did not. This meta-analysis provides evidence that thromboprophylaxis can reduce the number of VTE and DVT events, with no apparent increase in the incidence of major bleeding in patients with cancer.

Parenteral anticoagulation in ambulatory patients with cancer

BACKGROUND

Anticoagulation may improve survival in patients with cancer through a speculated anti-tumour effect, in addition to the antithrombotic effect, although may increase the risk of bleeding.

OBJECTIVES

To evaluate the efficacy and safety of parenteral anticoagulants in ambulatory patients with cancer who, typically, are undergoing chemotherapy, hormonal therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

SEARCH METHODS

A comprehensive search included (1) a major electronic search (February 2016) of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (2016, Issue 1), MEDLINE (1946 to February 2016; accessed via OVID) and Embase (1980 to February 2016; accessed via OVID); (2) handsearching of conference proceedings; (3) checking of references of included studies; (4) use of the 'related citation' feature in PubMed and (5) a search for ongoing studies in trial registries. As part of the living systematic review approach, we are running searches continually and we will incorporate new evidence rapidly after it is identified. This update of the systematic review is based on the findings of a literature search conducted on 14 August, 2017.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the benefits and harms of parenteral anticoagulation in ambulatory patients with cancer. Typically, these patients are undergoing chemotherapy, hormonal therapy, immunotherapy or radiotherapy, but otherwise have no standard therapeutic or prophylactic indication for anticoagulation.

DATA COLLECTION AND ANALYSIS

Using a standardized form we extracted data in duplicate on study design, participants, interventions outcomes of interest, and risk of bias. Outcomes of interested included all-cause mortality, symptomatic venous thromboembolism (VTE), symptomatic deep vein thrombosis (DVT), pulmonary embolism (PE), major bleeding, minor bleeding, and quality of life. We assessed the certainty of evidence for each outcome using the GRADE approach (GRADE handbook).

MAIN RESULTS

Of 6947 identified citations, 18 RCTs fulfilled the eligibility criteria. These trials enrolled 9575 participants. Trial registries' searches identified nine registered but unpublished trials, two of which were labeled as 'ongoing trials'. In all included RCTs, the intervention consisted of heparin (either unfractionated heparin or low molecular weight heparin). Overall, heparin appears to have no effect on mortality at 12 months (risk ratio (RR) 0.98; 95% confidence interval (CI) 0.93 to 1.03; risk difference (RD) 10 fewer per 1000; 95% CI 35 fewer to 15 more; moderate certainty of evidence) and mortality at 24 months (RR 0.99; 95% CI 0.96 to 1.01; RD 8 fewer per 1000; 95% CI 31 fewer to 8 more; moderate certainty of evidence). Heparin therapy reduces the risk of symptomatic VTE (RR 0.56; 95% CI 0.47 to 0.68; RD 30 fewer per 1000; 95% CI 36 fewer to 22 fewer; high certainty of evidence), while it increases in the risks of major bleeding (RR 1.30; 95% 0.94 to 1.79; RD 4 more per 1000; 95% CI 1 fewer to 11 more; moderate certainty of evidence) and minor bleeding (RR 1.70; 95% 1.13 to 2.55; RD 17 more per 1000; 95% CI 3 more to 37 more; high certainty of evidence). Results failed to confirm or to exclude a beneficial or detrimental effect of heparin on thrombocytopenia (RR 0.69; 95% CI 0.37 to 1.27; RD 33 fewer per 1000; 95% CI 66 fewer to 28 more; moderate certainty of evidence); quality of life (moderate certainty of evidence).

AUTHORS' CONCLUSIONS

Heparin appears to have no effect on mortality at 12 months and 24 months. It reduces symptomatic VTE and likely increases major and minor bleeding. Future research should further investigate the survival benefit of different types of anticoagulants in patients with different types and stages of cancer. The decision for a patient with cancer to start heparin therapy should balance the benefits and downsides, and should integrate the patient's values and preferences.Editorial note:This is a living systematic review. Living systematic reviews offer a new approach to review updating in which the review is continually updated, incorporating relevant new evidence, as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.

Thromboprophylaxis in non-surgical cancer patients

Acutely ill medical patients with cancer and cancer patients requiring non-surgical therapy are considered as non-surgical cancer patients and are at moderate to high risk of venous thromboembolism (VTE): approximately 10-30% of these patients may develop asymptomatic or symptomatic deep-vein thrombosis (DVT) or pulmonary embolism (PE), and the latter is a leading contributor to deaths in hospital. Other medical conditions associated with a high risk of VTE include cardiac disease, respiratory disease, inflammatory bowel disease, rheumatological and infectious diseases. Pre-disposing risk factors in non-surgical cancer patients include a history of VTE, immobilisation, history of metastatic malignancy, complicating infections, increasing age, obesity hormonal or antiangiogenic therapies, thalidomide and lenalidomide therapy. Heparins, both unfractionated (UFH) and low molecular weight heparin (LMWH) and fondaparinux have been shown to be effective agents in prevention of VTE in the medical setting with patients having a history of cancer. UFH and LMWH along with semuloparin also have a role in outpatients with cancer receiving chemotherapy. However, it has not yet been possible to demonstrate a significant effect on mortality rates in this population. UFH has a higher rate of bleeding complications than LMWH. Thromboprophylaxis has been shown to be effective in medical patients with cancer and may have an effect on cancer outcomes. Thromboprophylaxis in patients receiving chemotherapy remains controversial and requires further investigation. There is no evidence for the use of aspirin, warfarin or mechanical methods. We recommend either LMWH, or fondaparinux for the prevention of VTE in cancer patients with acute medical illnesses and UFH for those with significant severe renal impairment. For ambulatory cancer patients undergoing chemotherapy we recommend LMWH or semuloparin. These are safe and effective agents in the thromboprophylaxis of non-surgical cancer patients.

Cancer-related venous thromboembolic disease: current management and areas of uncertainty

The relationship between cancer and venothromboembolic events is a complex, multifactorial process which is still not fully understood and therefore the use of current generic guidelines may be inadequate. Current management of cancer-related VTE may be suboptimal because of the lack of cancer-specific studies into the role of primary prophylaxis in both ambulant and non-ambulant cancer patients. Further research into developing cancer-specific risk assessment tools and the choice, dose and duration of prophylaxis is required. The management of confirmed symptomatic VTE in cancer patients is outlined but certain controversies remain. Areas for further research include the management of asymptomatic unsuspected VTE events, recurrent VTE events on treatment and the role of IVC filters and other treatment options are required. This paper attempts to cover some of the recent developments and areas of uncertainty surrounding the management of cancer-related VTE.

Prevention and treatment of venous thromboembolism in patients with cancer

Venous thromboembolism (VTE) is the second leading cause of death and a major cause of morbidity in patients with cancer. Pharmacologic thromboprophylaxis is recommended in all hospitalized cancer patients without contraindications to anticoagulants. The role of thromboprophylaxis in outpatients undergoing chemotherapy is less certain because of the diversity of the tumor types and their associated risks of VTE and bleeding. Thromboprophylaxis should only be considered in patients at high risk for VTE. Cancer patients with a newly diagnosed VTE should be preferably treated with low-molecular-weight heparin for a minimum of 3-6 months. Treatment duration should be individualized based on the clinical status and stage of the cancer, the risk of recurrent VTE, the risk of bleeding, and personal preference of the patient. Further research is required to assess the role of the new oral anticoagulants (direct Xa and thrombin inhibitors) for this high-risk population.

Prediction of Venous Thromboembolism in Patients With Cancer by Measuring Thrombin Generation: Results From the Vienna Cancer and Thrombosis Study

Purpose

Patients with cancer are at increased risk of venous thromboembolism (VTE). Laboratory tests measuring the overall thrombophilic tendency might be useful to assess VTE risk. The aim of this study was to investigate thrombin generation, a key process in hemostasis, as predictor of cancer-associated VTE.

Patients and Methods

The Vienna Cancer and Thrombosis Study (CATS) is a prospective observational cohort study of patients with newly diagnosed cancer or progression of disease after remission. The study end point is occurrence of objectively confirmed symptomatic or fatal VTE within a follow-up period of 2 years. Thrombin generation was measured with a commercially available assay.

Results

One thousand thirty-three patients with malignancies of the breast (n = 151), lung (n = 148), upper (n = 44) and lower gastrointestinal tract (n = 125), pancreas (n = 67), kidney (n = 34), prostate (n = 122), and brain (n = 134) or lymphoma (n = 126), multiple myeloma (n = 26), and other tumor types (n = 56) were observed for a median observation period of 517 days. VTE occurred in 77 patients (7.5%). Patients with elevated peak thrombin (defined as values ≥ 611 nM thrombin, representing the 75th percentile of the total study population) had an increased risk of VTE with a hazard ratio of 2.1 (95% CI, 1.3 to 3.3, P = .002) in multivariable analysis including age, sex, surgery, chemotherapy, and radiotherapy. The cumulative probability of developing VTE after 6 months was significantly higher in patients with elevated peak thrombin than in those with lower peak thrombin (11% v 4%; log-rank test: P = .002).

Conclusion

Measurement of thrombin generation may help identify patients with cancer at high risk of VTE.

The Hemostasis Apparatus in Pancreatic Cancer and Its Importance beyond Thrombosis

Laboratory evidence of aberrant coagulation is found in the majority of patients with advanced pancreatic cancer and a clinical consequence of this is the high incidence and prevalence of vascular thromboembolic events. Other sequelae are hypothesized to be the facilitation and acceleration of mechanisms that define the malignant phenotype, such as invasion, trafficking and anchoring, establishing the metastatic niche and inducing angiogenesis. We review the in vitro and preclinical evidence that supports the role of the coagulation apparatus in the metastatic process of pancreatic cancer, with a particular emphasis on interaction of this pathway with clinically-targeted growth factor receptor pathways. Links between hemostasis, angiogenesis and epidermal growth factor pathways and their significance as therapeutic targets are considered.