The following article features coverage from the European Society of Medical Oncology (ESMO) Congress 2021. Click here to read more of Hematology Advisor’s conference coverage.

Intermediate anticoagulation doses appear to be safe and effective as thromboprophylaxis in patients with high thrombotic risk active cancer, according to the results of a study presented during the European Society for Medical Oncology (ESMO) Congress 2021.

ACT4CAT ( Identifier: NCT03909399) was a prospective observational study conducted by the Hellenic Society of Medical Oncology (HeSMO) to record real world data of clinical practice for thromboprophylaxis in ambulatory patients with high thrombotic risk active cancer. Participants were enrolled at 19 oncology departments.

A total of 628 patients enrolled in the study and 394 (62.7%) completed the trial. The presented analysis included 541 patients (86.1%) who had finished 2 visits, comprising 3 to 4 cycles of treatment. The mean age was 65.4±12.4 years and mean body mass index was 26.2±5.2 kg/m2.

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Among the patients, 78.1% had metastatic disease. Cancer types included pancreatic (27%), lung (26.6%), colorectal (10.7%), gastric (6.7%), ovarian (4.8%), and bladder (4.4%). Most patients (84.5%) had been treated with highly thrombogenic agents, including platinum (53.4%), antimetabolites (51.9%), and immunotherapy (11.8%). Of these agents, 53.8% had the potential to interact with direct oral anticoagulants.

At the time of the study, 61.1% and 18.0% of patients were receiving first- and second-line therapy respectively, while 9.2% and 3.1% were receiving adjuvant and neoadjuvant therapy. Approximately 60% of patients had a Khorana score of 2 or higher.

Administered anticoagulation included tinzaparin in 90.7%, fondaparinux in 5.2%, bemiparin in 2.0%, enoxaparin and rivaroxaban in 1.3%, and apixaban in 0.4% for an average duration of 5.5±3.7 months.

Regardless of clinical setting, 68.6% of patients received an intermediate dose of anticoagulant (first-line: 67.5%; second-line: 73.9%; adjuvant: 42.2%, and neoadjuvant: 66.7%; P =.0028). Thrombotic events occurred in 13 patients (2.4%) and 11 minor bleeding events were reported (2.0%).

“[Cancer-associated thrombosis] can negatively affect prognosis in patients with active cancer. Apart from Khorana score, high thrombotic risk tumors, metastasis, [highly thrombogenic agents], along with bleeding risk and drug-drug interactions, also influence the clinical decision for thromboprophylaxis,” wrote the authors.

“Intermediate anticoagulation doses as thromboprophylaxis are safe and effective in active cancer,” the researchers concluded.

Read more of Hematology Advisor’s coverage of ESMO 2021 by visiting the conference page.


Tsoukalas NG, Christopoulou AN, Timotheadou E, et al. Thromboprophylaxis in high-risk oncology patients: Is it a safe and effective clinical decision-intervention? Presented at: European Society for Medical Oncology (ESMO) Congress 2021; September 16-21, 2021. Abstract 1692P