Incidence and prevention of venous thromboembolism in patients undergoing breast cancer surgery and treated accordinq to clinical pathways

Objective: To minimize treatment variations, we have implemented clinical pathways for all breast cancer patients undergoing surgery. We sought to determine the incidence of postoperative venous thromboembolism (VTE) in patients treated on these pathways. Summary Background Data: Cancer patients have an increased risk of VTE because of a hypercoagulable state. The risk of VTE following breast cancer surgery is not well established. Methods: We retrospectively reviewed prospectively collected data for all patients who underwent breast cancer surgery and were treated on the clinical pathways with mechanical antiembolism devices and early ambulation in the postoperative period between January 2000 and September 2003. Results: During the study period, 3898 patients underwent 4416 surgical procedures. Seven patients with postoperative VTE within 60 days were identified, for a rate of 0.16% per procedure. Six patients presented with only a deep venous thrombosis or a pulmonary embolism; 1 patient had both. The median time from surgery to diagnosis of VTE was 14 days (range, 2-60 days; mean, 22 days). No relationship was identified between stage of breast cancer or type of breast surgery and development of VTE. Two (29%) of the 7 patients with VTE had received neoadjuvant chemotherapy. VTE treatment consisted of subcutaneous low-molecular-weight heparin (n = 5) or intravenous heparin (n = 2) followed by warfarin. There were no deaths. Conclusions: VTE following breast cancer surgery is rare in patients who are treated on clinical pathways with mechanical antiembolism devices and early ambulation in the postoperative period. We conclude that systemic VTE prophylaxis is not indicated in this group of patients.