Thromboembolic events in breast cancer patients: A large series.
9589 Background: Breast cancer is frequently associated with thromboembolic events (TEE). TEE may result in significant morbidity, a substantial economic burden and they represent a leading cause of death. Methods: We conducted a case-control study to analyze patients’ baseline and treatment characteristics in predicting TEE occurrence as well as the prognosis of breast cancer patients with thromboembolic events. We identified all breast cancer patients with a TEE at INCA (Brazilian National Cancer Institute), between January 2007 and December 2011. The control group consisted of breast cancer patients that had a doppler ultrasound with normal findings during the same period. Variables found to be significant (P <0.10) by univariate analysis were subsequently entered into a multivariate logistic regression model. We used Kaplan-Meier and Cox regression for survival analysis. Results: Overall, 225 patients that developed TEE were compared to 225 matched controls. The majority of events were deep vein thrombosis of the lower extremity (78.7%) and unilateral (94.2%). Most TEE occurred within the first 3 years after the diagnosis of cancer (66.2%), with the highest incidence observed in the initial 6 months. Factors associated with the development of TEE were: age above 50 years (OR 1.85, 95% CI: 1.16 to 2.95), ECOG performance status (PS) equal to or above 3 (OR 2.01, CI 95%: 1.24 to 3.26) and the presence of a central venous catheter (CVC) (OR 2.56, 95% CI: 1.42 to 4.62). The occurrence of TEE led to systemic treatment changes (44.9%) and, most importantly, it was associated with decreased survival (HR = 1.34, 95% CI: 1.01 to 1.77, p = 0.041). Conclusions: This large retrospective analysis of TEE in breast cancer patients confirms that most events occur early in the treatment course. The incidence of TEE was associated with patients’ age, PS, and the presence of CVC. Prospective studies are needed to evaluate outpatient thromboprophylaxis for selected groups of patients.