Breast Cancer Patients Are 30% More Likely To Develop Arterial Thromboembolic Events after Diagnosis Compared with Cancer-Free Women: Results from a Large Population-Based Study.

Background: Population-based prevalence and incidence data of arterial thromboembolic events (ATEE) in breast cancer (BC) patients are lacking in the published literature.Objectives: The occurrence of ATEE before and after BC diagnosis was compared with cancer-free controls in a population-based setting.Methods: Women who had a first hospitalization for BC between 2002 and 2007 were selected from the PHARMO Record Linkage System (RLS), which includes drug use and hospitalization data from approximately 3 million residents in the Netherlands. BC patients were matched 1:10 by age with cancer-free controls, using the date of diagnosis as the index date for both BC patients and controls. ATEE were defined as a myocardial infarction, unstable angina, ischemic stroke, and transient ischemic attack requiring hospitalization and were assessed 12 mo before and after the index date.Results: The analysis included 11,437 BC patients, with a mean ± SD age of 59 ± 14 years. ATEE before the index date were twice as frequent among BC patients compared with cancer-free controls (Table 1), though prevalence was 10 days during the first 6 months of follow-up.Conclusions: In this large population-based study, the occurrence of the arterial thromboembolic events was low. However, BC patients were at significantly higher risk of developing ATEE compared with cancer-free controls. These results emphasize the need for careful observation of BC patients after diagnosis. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2050.