O-163 Prevention of thromboembolic complications with the low-molecular-weight heparin certoparin in non-small-cell lung carcinoma (TOPIC-2)

Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy

BACKGROUND

Venous thromboembolism (VTE) often complicates the clinical course of cancer. The risk is further increased by chemotherapy, but the trade-off between safety and efficacy of primary thromboprophylaxis in cancer patients treated with chemotherapy is uncertain. This is the third update of a review first published in February 2012.

OBJECTIVES

To assess the efficacy and safety of primary thromboprophylaxis for VTE in ambulatory cancer patients receiving chemotherapy compared with placebo or no thromboprophylaxis, or an active control intervention.

SEARCH METHODS

For this update, the Cochrane Vascular Information Specialist searched the Cochrane Vascular, CENTRAL, MEDLINE, Embase and CINAHL databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 3 August 2020. We also searched the reference lists of identified studies and contacted content experts and trialists for relevant references.

SELECTION CRITERIA

Randomised controlled trials comparing any oral or parenteral anticoagulant or mechanical intervention to no thromboprophylaxis or placebo, or comparing two different anticoagulants.

DATA COLLECTION AND ANALYSIS

We extracted data on risk of bias, participant characteristics, interventions, and outcomes including symptomatic VTE and major bleeding as the primary effectiveness and safety outcomes, respectively. We applied GRADE to assess the certainty of evidence.

MAIN RESULTS

We identified six additional randomised controlled trials (3326 participants) for this update, bringing the included study total to 32 (15,678 participants), all evaluating pharmacological interventions and performed mainly in people with locally advanced or metastatic cancer. The certainty of the evidence ranged from high to very low across the different outcomes and comparisons. The main limiting factors were imprecision and risk of bias. Thromboprophylaxis with direct oral anticoagulants (direct factor Xa inhibitors apixaban and rivaroxaban) may decrease the incidence of symptomatic VTE (risk ratio (RR) 0.43, 95% confidence interval (CI) 0.18 to 1.06; 3 studies, 1526 participants; low-certainty evidence); and probably increases the risk of major bleeding compared with placebo (RR 1.74, 95% CI 0.82 to 3.68; 3 studies, 1494 participants; moderate-certainty evidence). When compared with no thromboprophylaxis, low-molecular-weight heparin (LMWH) reduced the incidence of symptomatic VTE (RR 0.62, 95% CI 0.46 to 0.83; 11 studies, 3931 participants; high-certainty evidence); and probably increased the risk of major bleeding events (RR 1.63, 95% CI 1.12 to 2.35; 15 studies, 7282 participants; moderate-certainty evidence). In participants with multiple myeloma, LMWH resulted in lower symptomatic VTE compared with the vitamin K antagonist warfarin (RR 0.33, 95% CI 0.14 to 0.83; 1 study, 439 participants; high-certainty evidence), while LMWH probably lowers symptomatic VTE more than aspirin (RR 0.51, 95% CI 0.22 to 1.17; 2 studies, 781 participants; moderate-certainty evidence). Major bleeding was observed in none of the participants with multiple myeloma treated with LMWH or warfarin and in less than 1% of those treated with aspirin. Only one study evaluated unfractionated heparin against no thromboprophylaxis, but did not report on VTE or major bleeding. When compared with placebo or no thromboprophylaxis, warfarin may importantly reduce symptomatic VTE (RR 0.15, 95% CI 0.02 to 1.20; 1 study, 311 participants; low-certainty evidence) and may result in a large increase in major bleeding (RR 3.82, 95% CI 0.97 to 15.04; 4 studies, 994 participants; low-certainty evidence). One study evaluated antithrombin versus no antithrombin in children. This study did not report on symptomatic VTE but did report any VTE (symptomatic and incidental VTE). The effect of antithrombin on any VTE and major bleeding is uncertain (any VTE: RR 0.84, 95% CI 0.41 to 1.73; major bleeding: RR 0.78, 95% CI 0.03 to 18.57; 1 study, 85 participants; very low-certainty evidence).

AUTHORS' CONCLUSIONS

In ambulatory cancer patients, primary thromboprophylaxis with direct factor Xa inhibitors may reduce the incidence of symptomatic VTE (low-certainty evidence) and probably increases the risk of major bleeding (moderate-certainty evidence) when compared with placebo. LMWH decreases the incidence of symptomatic VTE (high-certainty evidence), but increases the risk of major bleeding (moderate-certainty evidence) when compared with placebo or no thromboprophylaxis. Evidence for the use of thromboprophylaxis with anticoagulants other than direct factor Xa inhibitors and LMWH is limited. More studies are warranted to evaluate the efficacy and safety of primary prophylaxis in specific types of chemotherapeutic agents and types of cancer, such as gastrointestinal or genitourinary 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.

Parenteral anticoagulation in ambulatory patients with cancer

BACKGROUND

Anticoagulation may improve survival in patients with cancer through an antitumor effect in addition to the perceived antithrombotic effect.

OBJECTIVES

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

SEARCH METHODS

A comprehensive search included (1) an electronic search (February 2013) of the following databases: Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 1), MEDLINE (1966 to February 2013; accessed via OVID) and EMBASE(1980 to February 2013; 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.

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 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 methodological quality, participants, interventions and outcomes of interest including all-cause mortality, symptomatic venous thromboembolism (VTE), symptomatic deep vein thrombosis (DVT), symptomatic pulmonary embolism (PE), arterial thrombosis (e.g. stroke, myocardial infarction), major bleeding, minor bleeding and quality of life.

MAIN RESULTS

Of 9559 identified citations, 15 RCTs fulfilled the eligibility criteria. These trials enrolled 7622 participants for whom follow-up data were available. In all included RCTs the intervention consisted of heparin (either unfractionated heparin or low molecular weight heparin). Overall, heparin may have a small effect on mortality at 12 months and 24 months (risk ratio (RR) 0.97; 95% confidence interval (CI) 0.92 to 1.01 and RR 0.95; 95% CI 0.90 to 1.00, respectively). Heparin therapy was associated with a statistically and clinically important reduction in venous thromboembolism (RR 0.56; 95% CI 0.42 to 0.74) and a clinically important increase in the risk of minor bleeding (RR 1.32; 95% 1.02 to 1.71). Results failed to show or to exclude a beneficial or detrimental effect of heparin on major bleeding (RR 1.14; 95% CI 0.70 to 1.85) or quality of life. Our confidence in the effect estimates (i.e. quality of evidence) was high for symptomatic venous thromboembolism, moderate for mortality, major bleeding and minor bleeding, and low for quality of life.

AUTHORS' CONCLUSIONS

Heparin may have a small effect on mortality at 12 months and 24 months. It is associated with a reduction in venous thromboembolism and a likely increase in 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 for survival benefit should balance the benefits and downsides, and should integrate the patient's values and preferences.

Parenteral anticoagulation may prolong the survival of patients with limited small cell lung cancer: a Cochrane systematic review

BACKGROUND

To determine the efficacy and safety of heparin (unfractionated heparin (UFH) or low-molecular-weight-heparin (LMWH)) and fondaparinux in improving the survival of patients with cancer.

METHODS

We conducted in January 2007 a comprehensive search for relevant randomized clinical trials (RCTs). We used a standardized form to extract in duplicate data on methodological quality, participants, interventions and outcomes of interest including all cause mortality, thromboembolic events, and bleeding events. We assessed the methodological quality for each outcome by grading the quality of evidence using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology

RESULTS

Of 3986 identified citations, we included 5 RCTs, none of which evaluated fondaparinux. The quality of evidence was moderate for survival, low for major and minor bleeding, and very low for DVT. Heparin therapy was associated with a statistically and clinically significant survival benefit (hazard ratio (HR) = 0.77; 95%CI = 0.65-0.91). In subgroup analyses, patients with limited small cell lung cancer experienced a clear survival benefit (HR = 0.56; 95%CI = 0.38-0.83). The survival benefit was not statistically significant for either patients with extensive small cell lung cancer (HR = 0.80; 95%CI = 0.60-1.06) or patients with advanced cancer (HR = 0.84; 95%CI = 0.68-1.03). The increased risk of bleeding with heparin was not statistically significant (relative risk (RR) = 1.78; 95%CI = 0.73-4.38).

CONCLUSION

This review suggests a survival benefit of heparin in cancer patients in general, and in patients with limited small cell lung cancer in particular.