Clinical practice guidelines for the treatment and prevention of cancer-associated thrombosis

The risk of venous thromboembolism (VTE) is increased in patients with cancer and is greatest in those with cancers of the pancreas, stomach, brain, lung and ovary, late stage disease and in those undergoing treatment including chemotherapy, hormonal therapy, or surgery. VTE in patients with cancer is associated with a variety of adverse consequences including an increased risk of VTE recurrence, major bleeding, and early mortality. A VTE risk score for ambulatory patients receiving cancer chemotherapy has been extensively validated and has been used to select high risk patients for thromboprophylaxis trials. Several randomized controlled trials (RCTs) and meta-analyses of these trials have confirmed that LMWHs can significantly reduce the risk of VTE in patients with cancer. While the direct oral anticoagulants (DOACs) have been approved for the general population, previous guideline panels discouraged their use due to a lack of cancer-specific data. Recently RCTs for the treatment of established VTE in patients with cancer have demonstrated that the risk of recurrent VTE is lower while the risk of bleeding greater with DOACs compared to LMWH. Two thromboprophylaxis trials comparing low dose DOACs to placebo in high risk patients receiving cancer therapy have recently reported similar rates of VTE occurrence at 6 months in the control arms. A meta-analysis of the pooled results from these trials in higher risk ambulatory patients receiving cancer therapy confirmed a significant reduction in overall VTE incidence as well as pre-planned secondary outcomes on treatment. Several clinical practice guidelines addressing VTE in patients with malignant disease have been updated including those from the American Society of Clinical Oncology (ASCO). The addition of DOACs as an option for the management of VTE in patients with cancer is the latest major change to previous guidelines issued by these organizations. The updated recommendations from these guidelines are summarized in this review.