At the 63^rd ASH Annual Meeting & Exposition, researchers from Northwestern University shared results from a pilot program designed to expedite referrals for oncology patients with cancer-associated thrombosis (CAT) in an effort to improve management and selection of needed therapies.

The nonmalignant hematology group worked in collaboration with their process improvement team from Northwestern Medicine to establish the Cancer-Associated Thrombosis clinic in April 2020.

“Venous thromboembolism (VTE) is a common consequence for patients with malignancy, and adversely impacts quality of life, morbidity and mortality,” explain the researchers. “While historically low-molecular weight heparin (LMWH) was considered standard of care for treatment of [CAT], more recent data support the safety and efficacy of direct oral anticoagulants (DOACs).”

Patients with CAT currently have limited access to thrombosis experts due to a national shortage of nonmalignant hematologists, as well as face challenges with navigating treatment due to the complex nature of their disease state.

For the purpose of the pilot program, patients were “referred from the Robert H. Lurie Comprehensive Cancer Center for either: (1) newly diagnosed (‘acute’) VTE that could be managed in an outpatient setting, or (2) “ongoing management” of an established VTE diagnosis.”

The researchers set a goal of meeting with acute referrals within 24 business hours and ongoing management referrals within two weeks. Initial visits were conducted by advanced practice providers and included a case discussion with an attending nonmalignant hematologist and pharmacist review for anticoagulant eligibility and teaching. Patients then received a 3-month follow up. Perceived bleeding risk, tumor type, drug interactions, and patient preferences were anticoagulant-determining factors.

In the first year of the pilot program—April 2020 to April 2021—63 patients were seen. Fifty-nine percent were women with a median age of 63 years, 20.6% had prior history of VTE, and 6.3% had a prior history of bleeding.

The most common tumor types represented were gastrointestinal (33.3%); gynecological (22.2%); hematological malignancies (14.2%), and breast (7.9%).

“Among 18 patients (28.5%) referred for acute VTE, the median time to appointment was 0 days, and among 45 patients (71.4%) referred for ongoing VTE management, the median time to appointment was 10 days,” reported the researchers. “The most common VTE was pulmonary embolism (PE) (25.4%), followed by proximal deep vein thrombosis (DVT) (20.6%), concurrent PE and DVT (14.3%) and upper extremity DVT (11.1%). Additionally, 7.9% of thrombotic events involved splanchnic vein and 4.8% cerebral veins (1 isolated, 2 together with DVT and/or PE).”

Twenty-eight patients (44.4%) were recommended enoxaparin and 29 patients (46%) were recommended DOACs (19 apixaban, 9 rivaroxaban, 1 edoxaban). Only 4 patients were advised to discontinue anticoagulants and 1 was advised to continue warfarin due to prior DOAC failure and patient-preference.

The most common reasons 44.4% of patients were advised to take enoxaparin over a DOAC included perceived bleeding risk/tumor type (50%), DOAC failure (21.4%), and drug to drug interactions (17.8%). At follow-up, 13 patients opted to switch to a different anticoagulant and 7 switched to a DOAC. A total of 37 patients had a follow-up visit, at which point 5 patients experienced recurrent or progressive VTE, and 7 patients reported bleeding events. Fifteen patients died during follow-up.

“While DOACs are increasingly prescribed for treatment of CAT, we found that DOACs were not our recommended anticoagulant in over half of patients referred to our clinic, largely due to perceived risk of bleeding/tumor type,” concluded the researchers. “This highlights the complexity of management of CAT, and demonstrates the benefit of dedicated thrombosis expertise to aid in management of CAT.”

Reference:
Martin KA, Laub C, Kalhagen L, et al. Improving hematology clinic access for patients with cancer-associated thrombosis. Poster presented at: 63rd ASH Annual Meeting & Exposition; December 11-14, 2021; Atlanta, GA.