Bleeding complications from warfarin anticoagulation in patients with malignancy

Bleeding complications from warfarin anticoagulants were analyzed in 431 patients with carcinoma of the lung, colon, prostate and head and neck who were admitted to a randomized, controlled therapeutic trial of this agent. A total of 215 patients were randomized to the warfarin-treated group and 216 to the control groups. The mean prothrombin time was significantly prolonged (p = 0.0001) for warfarin-treated patients. The duration of warfarin administration was 64.9% of the total followup period providing 101 patient-years of experience with warfarin in cancer. Both the overall incidence of bleeding episodes (58% of warfarin-treated versus 30% of control) and the incidence of major bleeding episodes (42% versus 14%, respectively) were significantly increased in the warfarin-treated group (p = less than 0.001). The incidence of major bleeding was 1.86 per patient-year on warfarin. The most common sites of bleeding (in descending order) were the gastointestinal tract, the urinary tract, the nasal passages and skin. Hemorrhage occurred in association with the terminal event in 10 warfarin-treated and 12 control patients. Warfarin anticoagulation may have contributed to terminal bleeding in 3 (1.4%) patients. There was no difference in mean hemoglobin or hematocrit values for patients with versus patients without bleeding episodes.