Abstract P3-12-08: Venous thromboembolism in patients receiving chemotherapy for breast cancer

Abstract

Abstract Background Venous thromboembolism (VTE) is an important cause of morbidity and mortality in patients with cancer. Current guidelines state that thromboprophylaxis is not required for patients receiving adjuvant chemotherapy but may be considered in certain high risk patients. The reported incidence of VTE during adjuvant treatment for breast cancer varies from 2.1 to 13.6%. In addition to traditional risk factors for VTE a pre-chemotherapy platelet count greater than 350 × 10/l has been suggested to be an independent risk factor for VTE in cancer patients. This study was performed to determine the incidence of VTE of patients in our centre and attempt to identify patients that may benefit from prophylaxis. Method Patients receiving chemotherapy for locally advanced and early breast cancer were identified within a 12 month period between January and December 2012. Case notes and electronic records were analysed and data was collected retrospectively on patient demographics, chemotherapy regimen prescribed, diagnosis of venous thromboembolic event and pre-treatment platelet count. Results A total of 271 patients were included in the study period, 269 were female, median age was 54 year (range 27 to 78). Adjuvant therapy was the indication in 219 and neo-adjuvant in 52 patients. 5-Fluorouracil, Epirubin, Cyclophosphamide (FEC) was administered in 127 patients and 144 patients received FEC-T (Taxotere). All patients were symptomatic and diagnosed according to local practice. Six patients were diagnosed with pulmonary emboli. Four of these patients had massive pulmonary emboli as defined by; extensive thromboembolic load and right heart strain and chemotherapy was ceased in three of these. Nine patients had upper limb deep venous thrombosis (DVT) and four patients had lower limb DVT. Two patients had risk factors for VTE and one was a consequence of a central venous catheter. Incidence of VTE in the 12 month study period for all patients was found to be 7%, the incidence in the neo-adjuvant group was 7.7% (4/52) and in the adjuvant group 6.8% (15/219). Mean baseline platelet count was 306 in the non-VTE group, 366 in the VTE group. Mean difference in platelet count was 60, (95% CI 9.9 – 111.4). p = 0.02 using independent t test. Discussion Our study indicates that, when evaluated, the incidence of VTE is relevant from a clinical point of view. The association between cancer and VTE has been well described. Most of the published studies analysed a heterogeneous population, with majority of patients having metastatic disease. In this study we determined the incidence of symptomatic VTE during adjuvant treatment therefore demonstrating the contribution of chemotherapy alone towards thrombogenicity. We would support the evidence that baseline platelet count is a significant risk factor, and this may inform our selection of patients for thromboprophylaxis. More research is required to investigate the factors involved in VTE in patients receiving adjuvant chemotherapy. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-08.