Patients with breast cancer have more than 2 times the risk for developing a venous thromboembolism 5 years after diagnosis compared with the general population, a study published in the journal Cancer has shown.1

Numerous studies have demonstrated the increased risk of venous thromboembolism associated with cancer and anticancer treatments; however, for this study researchers sought to evaluate the risk and clinical predictors of venous thromboembolism in patients with breast cancer with respect to time since diagnosis.

Investigators analyzed data from 8338 Swedish patients with breast cancer diagnosed between 2001 and 2008 and 39,013 age-matched control subjects from the general population.

At a median follow-up of 7.2 years, a total of 426 patients with breast cancer experienced a venous thromboembolism event. Researchers found that patients with cancer had a 3-fold increased risk of venous thromboembolism vs those in the general population (hazard ratio [HR], 3.28; 95% CI, 2.87-3.74).

The study demonstrated that the risk of venous thromboembolism was highest 6 months after cancer diagnosis (HR, 8.62; 95% CI, 6.56-11.33), with a sustained increased risk at 5 years (HR, 2.19; 95% CI, 1.80-2.67).

The study further showed that older age, being overweight, preexisting venous thromboembolism, comorbid disease, tumor size less than 40 mm, progesterone receptor-negative status, more than 4 affected lymph nodes, and receipt of chemotherapy and endocrine therapy were independently associated with an increased risk of venous thromboembolism.

Comorbid disease and progesterone receptor-negative status were more strongly associated with late-onset events, while the effect of chemotherapy was limited to early onset events.

Reference

1. Brand JS, Hedayati E, Bhoo-Pathy N, et al. Time-dependent risk and predictors of venous thromboembolism in breast cancer patients: A population-based cohort study. Cancer. 2016 Oct 11. doi: 10.1002/cncr.30364. [Epub ahead of print]