Physicians' decision about long-term thromboprophylaxis in cancer outpatients: CAT AXIS, a case vignette study on clinical practice in France

Data on long-term venous thromboembolism prophylaxis in cancer outpatients remain scarce. In the absence of clear and consistent treatment guidelines, our objectives were to describe and better understand clinical practice and to identify factors influencing the use of thromboprophylaxis. CAT AXIS was a multicentred cross-sectional study based on the completion of physician-profile questionnaires and the assessment of 10 e-mailed credible clinical scenarios of lung, colon and breast cancers by each of participants using the case vignette-validated method. A total of 224 physicians participated allowing the completion and the analysis of 2085 reviewed case vignettes corresponding to 765, 703 and 617 fictive clinical scenarios on lung, colon and breast cancers, respectively. The overall rate of thromboprophylaxis was 680/2085 (32.6%) among participants with a comparable proportion for the three types of cancer. Low-molecular-weight heparin (LMWH) was the most frequently used, by 92.7, 93.8 and 83.9% of participants for lung, colon and breast cancers, respectively; thromboprophylaxis duration of 3 months was used by 74.4% of participants. Multivariate analyses revealed that the Eastern Cooperative Oncology Group index, metastatic malignancy, chemotherapy and history of thrombosis were significantly associated with the therapeutic decision unlike Khorana score and anaemia. In the absence of clear guidance, the use of thromboprophylaxis remains low and rather empiric even though the selection of LMWH by the majority of participants and treatment duration seems appropriate based on available data to date. Specific guidelines with corresponding awareness are required.