In the early maintenance (up to 6 months) setting, the expert panel recommended use of LMWHs rather than vitamin K antagonists when creatinine clearance is 30 mL/min or above. Moreover, the panel stated that direct oral anticoagulants (DOACs) can also be used, but caution should be exercised when treating patients with gastrointestinal tract malignancies. Anticoagulation therapy should be maintained for at least 6 months in this setting. Beyond 6 months, the decision to continue anticoagulation should be individualized to the patient, as evidence to guide treatment after 6 months is limited.

In cases of VTE recurrence, other alternatives may be considered, such as increasing the LMWH dose by 20% to 25% or changing treatment regimens from LMWH to DOAC, DOAC to LMWH, or vitamin K antagonist to DOAC or LMWH as applicable.

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VTE Prophylaxis in Patients With Cancer

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The recommendations in this section focused on 3 key areas: prophylaxis of VTE in patients who have undergone surgery, prophylaxis in patients with medical cancer, and prophylaxis of catheter-related thrombosis.

The panel recommended use of LMWH once daily for patients with a creatinine clearance of 30 mL/min or higher or low-dose unfractionated heparin 3 times daily for prophylaxis in patients with cancer who have undergone surgery. With respect to LMWH dosing, the highest prophylactic dose should be given. At present, there is inadequate evidence to recommend fondaparinux as a substitute for LMWH to prevent VTE in postoperative patients with cancer.

In patients with cancer who have reduced mobility or patients who are hospitalized, the panel recommended LMWH or fondaparinux when creatinine clearance is 30 mL/min or above. Unfractionated heparin is also an option for these patients. Currently, DOACs are not routinely recommended in this setting. In addition, primary prophylaxis with vitamin K antagonists, LMWH, or DOACs is not recommended for patients receiving systemic anticancer treatment in the ambulatory setting.

VTE Treatment in Special Situations

In patients with a brain tumor, DOACs or LMWH can be used for the treatment of established VTE. Postoperative prophylaxis with LMWH or unfractionated heparin is recommended for patients undergoing neurosurgery but not for patients not undergoing surgery.

In patients with severe renal dysfunction (defined as creatinine clearance < 30 mL/min), an external compression device can be used, and the decision to initiate pharmacologic prophylaxis should be individualized. Pharmacologic prophylaxis should be decided on an individual basis for patients with thrombocytopenia as well.

In obese patients, a higher dose of LMWH should be considered in the surgical setting. 

Unanswered Questions

Alok Khorana, MD, of the department of medicine at Case Western Reserve University in Cleveland, Ohio, and coauthor of the guidelines, told Hematology Advisor, “Although the initial treatment (up to 6 months) of cancer-associated VTE is well established (using DOACs or LMWH), it [remains] unclear what to do after 6 months of treatment.”

He continued, “[In] general, [the] recommendation is to remain on anticoagulation for as long as the active malignancy [is present], but this is a major unmet need [requiring more] evidence.”

Additional studies are needed to better understand the optimal duration of anticoagulation therapy in patients with active malignancy.

Disclosures: Some authors have declared affiliations with the pharmaceutical industry. Please refer to the original study for a full list of disclosures.


1. Farge D, Frere C, Connors JM, et al. International Initiative on Thrombosis and Cancer (ITAC) advisory panel. 2019 international clinical practice guidelines for the treatment and prophylaxis of venous thromboembolism in patients with cancer [published online September 3, 2019]. Lancet Oncol. doi:10.1016/S1470-2045(19)30336-5