The following article is a part of conference coverage from the American College of Cardiology’s 70th Annual Scientific Session & Expo is being held virtually from May 15 to 17, 2021. The team at Cardiology Advisor will be reporting on the latest news and research conducted by clinicians and scientists in the field. Check back for more from the ACC 2021 .

The results of a systematic review and meta-analysis show that direct oral anticoagulants (DOACs) are superior to low molecular weight heparin (LMWH) for preventing recurrence of cancer-associated venous thromboembolism. These findings were presented during the American College of Cardiology Annual Meeting held virtually May 15 to 17, 2021.

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Researchers from the University of Toledo in Ohio searched publication databases for studies published between 2018 and 2020 about venous thromboembolism recurrence among patients with cancer who were treated with DOACs or LMWH. A total of 4 randomized controlled trials and 2 cohort studies comprising 3715 patients with cancer who had venous thromboembolisms were included in this analysis.

Patients were treated with DOACs (n=1881) or LMWH (n=1834).

After a mean follow-up of 6.1 months, venous thromboembolism recurrences were lower among patients treated with DOACs (n=105/1881) compared with LMWH (n=158/1834), which corresponded with a risk ratio (RR) of 0.60 (95% CI, 0.42-0.86). No significant study heterogeneity was observed (t2, 0.08; c2, 8.90; P =.11; I2, 44%).

No risk differences for major bleeding events (RR, 1.23; 95% CI, 0.92-1.65; I2, 0%) or all-cause mortality (RR, 0.95; 95% CI, 0.83-1.09; I2, 44%) were observed.

Patients treated with DOACs had higher instances of clinically relevant nonmajor bleeding events (n=180/1833) compared with patients treated with LMWH (n=119/1811), corresponding with an RR of 1.53 (95% CI, 1.13-2.08). No evidence of heterogeneity among underlying studies was detected (t2, 0.04; c2, 5.98; P =.20; I2, 33%).

This study was limited by the small number of patients included. It remains unclear whether risk for cancer-associated venous thromboembolism may differ among cancer subgroups.

These data indicated DOACs more effectively prevented recurrence of venous thromboembolism among patients with cancer than LMWH. Neither major bleeding events nor all-cause mortality differed between patient groups. DOACs, however, were associated with increased risk for nonmajor, clinically relevant bleeding events.


Mhanna M, Shastri P, Burmeister C, et al. Efficacy and safety of direct oral anticoagulants versus low molecular weight heparin in cancer associated venous thromboembolism: a systematic review and meta-analysis. Presented at: American College of Cardiology Annual Meeting; May 15-17, 2021.

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