Which chemopreventive agents for postmenopausal early breast cancer?

Postmenopausal women taking adjuvant aromatase inhibitors (AIs) for early breast cancer are statistically at significantly greater risk for grade 3 and 4 cardiovascular events than women receiving tamoxifen; however, the absolute difference is relatively low with 160 to 180 patients needing to be treated to produce one event. The data come from a meta-analysis of seven randomized clinical trials involving almost 20,000 patients.

When making decisions regarding these AIs, the authors of the meta-analysis state that clinicians and their patients must balance these figures regarding cardiotoxicity against the risk of thromboembolic events, which is significantly higher in women receiving tamoxifen (RR, 0.53; 95% CI, 0.42–0.65; P<.0001), and against the risks for stroke and endometrial carcinoma, which are also associated with tamoxifen. Other considerations include bone toxicity associated with AIs, keeping in mind that promising data are emerging regarding the role of bisphosphonates to mitigate fracture risk in AI therapy, and that general toxicity seems lower and disease-free survival higher with AI therapy.

Cuppone F, Bria E, Verma S, et al. Do adjuvant aromatase inhibitors increase the cardiovascular risk in postmenopausal women with early breast cancer? Meta-analysis of randomized trials. Cancer. 2008;112:260-267.