Women receiving chemotherapy for breast cancer have a clinical important risk for developing venous thromboemboli (VTE), while women receiving tamoxifen have an increased risk of VTE immediately following endocrine therapy, a new study published online ahead of print in the journal Blood has shown.1
Although previous research have demonstrated that patients with breast cancer are at an increased risk for developing VTE, especially in the peridiagnosis period, the effect of breast cancer treatment on VTE risk is unknown. Therefore, researchers sought to evaluate the impact of breast cancer stage, biology, and treatment on the risk of VTE.
For the study, researchers analyzed data from 13 202 patients with breast cancer from the Clinical Practice Research Datalink in England. Patients’ breast cancer was diagnosed between 1997 and 2006 and had follow-up continuing to the end of 2010.
Results showed that patients with breast cancer had an annual VTE incidence of 6% while undergoing chemotherapy and in the month following treatment, which was 10.8-fold higher than women who did not receive chemotherapy.
Researchers also found that patients receiving tamoxifen had a 4-times higher risk for developing VTE immediately following endocrine therapy than the risk before initiating therapy.
The risk of VTE following surgery was also significantly increased during the first month after surgery, but it was not raised after the first month.
1. Walker AJ, West J, Card TR, et al. When are breast cancer patients at highest risk of venous thromboembolism: a cohort study using English healthcare data [published online ahead of print November 16, 2015]. Blood. doi:10.1182/blood-2015-01-625582.