Apixaban and Dalteparin for the Treatment of Venous Thromboembolism in Patients with Different Sites of Cancer.

Efficacy and safety of anticoagulant treatment for venous thromboembolism (VTE) may vary in patients with different cancer sites. We evaluated the rates of VTE recurrence and major bleeding and the relative efficacy and safety of 6-month treatment with oral apixaban or subcutaneous dalteparin in patients with different cancer sites randomized in the Caravaggio study. Primary cancer was located at gastrointestinal sites in 375 patients (32.5%), lung in 200 (17.3%), breast in 155 (13.4%), genitourinary sites in 139 (12%), gynecological sites in 119 (10.3%), and was hematological in 85 patients (7.4%). Rates of VTE recurrence were 10.9% in patients with gynecological, 8.8% with gastrointestinal, 6.5% with genitourinary, and 5.5% with lung cancer with lower rates in the other sites of cancer. Rates of major bleeding were 7.2% in patients with genitourinary and 4.8% with gastrointestinal cancer, with lower rates in patients with other sites of cancer. The observed absolute risk difference in VTE recurrence in favor of apixaban was 11.9% in patients with gynecological, 5.5% with lung, 3.7% with genitourinary cancer, and 0.6% with gastrointestinal cancer. None of the risk differences was statistically significant. The rates of major bleeding in patients treated with apixaban or dalteparin was similar across patients with different cancer sites. In conclusion, recurrences appear to be more common in patients with gastrointestinal and gynecological cancer and major bleedings in patients with genitourinary and gastrointestinal cancer. Oral apixaban is a valid oral alternative to subcutaneous dalteparin for the treatment of a large spectrum of patients with cancer-associated VTE.