Primary ambulatory thromboprophylaxis in patients with pancreatic cancer receiving chemotherapy: hope or hype?

Thrombosis is the second leading cause of death in cancer patients. Patients with pancreatic cancer (PC) have a very high risk of developing venous thromboembolism (VTE). Even though primary ambulatory thromboprophylaxis (PATP) could decrease this risk, there are uncertain issues with regard to the choice and dose of anticoagulants, duration of anticoagulant therapy, and patient selection criteria. In addition, the current practice guidelines on PATP in PC patients are equivocal. This review critically appraises the evidence on the use of PATP in PC patients receiving chemotherapy.

Impact of Primary Ambulatory Thromboprophylaxis (PATP) with Low-Molecular Weight Heparins (LMWHs) on Survival in Patients with Lung Cancer Receiving Chemotherapy.

Lung cancer (LC) is the leading cause of cancer mortality. PATP was provided in experimental trials to decrease the venous thromboembolism (VTE), with ultimate aim to improve overall survival (OS). We undertook an updated systematic review and meta-analysis of randomized controlled trials (RCTs) to determine the impact of PATP with LMWHs on OS and VTE in patients with LC. 5443 patients with LC from nine RCTs were included. The pooled hazard ratio (HR) for OS was 1.02 (95% CI 0.83 to 1.26; P = 0.83) and for progression or metastasis-free survival was 1.03 (95% CI 0.86 to 1.24; P = 0.74). The pooled risk ratio (RR) for VTE was 0.54 (95% CI 0.43 to 0.69; P < 0.00001) and the risk difference (RD) was-0.03 (- 0.05 to - 0.02; P < 0.00001). Our analysis showed no survival advantage with the addition of PATP with LMWHs to standard chemotherapy in patients with LC, regardless of histology or stages of small cell LC.

Meta-analysis of randomized controlled trials on primary ambulatory thromboprophylaxis in patients with ovarian cancer receiving chemotherapy.

Ovarian cancer (OC) is highly associated with venous thromboembolism (VTE). The OC cells stimulate thrombin generation, and chemotherapy potentiates the prothrombotic effect of cancer cells by damaging endothelium and enhancing hypercoagulability. Recently, primary ambulatory thromboprophylaxis (PATP) has been studied as a potential treatment in cancer patients undergoing chemotherapy with an aim of reducing the incidence of VTE and potentially prolonging survival. A meta-analysis was performed of randomized controlled trials of PATP vs control in patients with OC receiving chemotherapy. The primary outcome measure was the incidence of VTE. The secondary outcome measure was the incidence of major bleeding complications. Two articles published between 2012 and 2020 fulfilled selection criteria. The incidence of VTE was 0.9% in the PATP group and 1.8% in the control group. However, the pooled risk ratio was not statistically significant at 0.69 (95% CI: 0.08 to 5.67; P = 0.73). The absolute risk difference was -0.03 (95% CI, -0.17 to 0.11; P = 0.66). There was no statistically significant reduction in VTE by providing PATP to patients with OC receiving chemotherapy. Routine PATP should not be recommended in ambulatory OC patients. Future randomized trials are necessary to define the high-risk subset of OC patients who may benefit from PATP.