Receipt of antihyperlipidemic agents during adjuvant endocrine therapy may be associated with reduced risk of breast cancer recurrence in patients with hormone receptor (HR)-positive early-stage breast cancer, according to a study published in the Journal of Clinical Oncology.1

Previous reports have suggested that cholesterol-lowering medication may have a role in preventing breast cancer recurrence by reducing levels of 27-hydroxycholesterol, an estrogenic cholesterol metabolite; however, aromatase inhibitors may counteract their intended effect by impacting cholesterol levels and hypercholesterolemia.

To evaluate the impact of cholesterol-lowering medications on breast cancer recurrence in women receiving adjuvant endocrine therapy, investigators enrolled 8010 postmenopausal women with early-stage, HR-positive breast cancer into the Breast International Group (BIG) 1-98 study, which compared the efficacy of adjuvant letrozole with that of tamoxifen.

In the double-blind, phase 3 trial (ClinicalTrials.gov Identifier: NCT00004205), researchers measured patients’ systemic levels of total cholesterol and use of antihyperlipidemic agents at enrollment and every 6 months up to 5.5 years.

Of the 789 patients who initiated cholesterol-lowering medications during adjuvant endocrine therapy, nearly half received letrozole monotherapy, 24% received sequential tamoxifen-letrozole, 22% received sequential letrozole-tamoxifen, and approximately 13% received tamoxifen monotherapy.

Results showed that cholesterol levels were reduced during treatment with tamoxifen. In addition, initiation of cholesterol-lowering medication reduced the risk of recurrence by 21% (hazard ratio [HR], 0.79; 95% CI, 0.66-0.95; P =.01).

Use of antihyperlipidemic agents was also associated with 24% improvement in the breast cancer-free interval (HR, 0.76; 95% CI, 0.60-0.97; P =.02) and a 26% improvement in distant recurrence-free interval (HR, 0.74; 95% CI, 0.56-0.97; P =.03).

Although these findings suggest that cholesterol-lowering medications may have a role in the prevention of breast cancer recurrence in postmenopausal women, further prospective randomized trials are needed to validate these observational results.

Reference

1. Borgquist S, Giobbie-Hurder A, Ahern TP, et al. Cholesterol, cholesterol-lowering medication use, and breast cancer outcome in the BIG 1-98 study. J Clin Oncol. 2017 Feb 13. doi: 10.1200/JCO.2016.70.3116 [Epub ahead of print]