The incidence of symptomatic thromboembolism in patients receiving adjuvant anthracycline-based chemotherapy for early stage breast cancer.

Thromboembolism is a well recognised complication of systemic chemotherapy and cancer. Its incidence is frequently not reported in clinical trials of adjuvant chemotherapy for early stage breast cancer. Our own experience suggested that thromboembolic complications were common and we undertook a retrospective review of consecutive patients receiving adjuvant chemotherapy to determine the incidence and morbidity/mortality of this complication. A total of 280 consecutive patients were identified who had received adjuvant ECMF chemotherapy between January 2001 and February 2007. Thromboembolic events occurred in 21 patients (7.5%). Events were distributed across chemotherapy cycles, but were more common during CMF chemotherapy (18 cases vs 3 cases). Patients over the age of 60 years appeared to be at particular risk of thromboembolism with an event rate of 27% (15/56 patients). Thromboembolic events were associated with dose delays and cessation of chemotherapy in some patients. With a median follow up of 28 months there is no significant difference in the incidence of breast cancer recurrence (16.7% vs 14.3%, p=0.9) or overall survival (89.5% vs 89.9%, p=0.8) between patients who experienced a thromboembolic event during adjuvant chemotherapy and those who did not. Based on the incidence of thromboembolism in our unselected patient population we believe that further prospective studies are indicated seeking to identify those patients at increased risk of this important complication who might benefit from thromboprophylaxis.