Cholesterol-lowering medication (CLM) use during adjuvant endocrine therapy may reduce risk of breast cancer recurrence in women with early-stage, hormone receptor (HR)–positive breast cancer, according to a study published in the Journal of Clinical Oncology.1
Previous studies suggest that CLM via statins may reduce breast cancer recurrence. It is hypothesized that CLM may inhibit estrogen receptor activation by the 17-hydroxycholesterol, an estrogenic cholesterol metabolite.
The purpose of this study was to evaluate the effect of CLM during adjuvant treatment with endocrine therapy among women with early-stage, HR-positive breast cancer.
This observational study evaluated data from the randomized, phase 3 BIG 1-98 trial (ClinicalTrials.gov Identifier: NCT00004205) of 8010 postmenopausal women with early-stage, HR-positive breast cancer. Women received adjuvant endocrine therapy with tamoxifen only, letrozole only, tamoxifen followed by letrozole, or letrozole followed by tamoxifen.
Total cholesterol levels and CLM use were recorded at enrollment, then every 6 months up to 5.5 years. Treatment with tamoxifen, but not letrozole, decreased serum cholesterol compared with baseline levels.
CLM was taken by 789 women during endocrine therapy. CLM use was associated with longer disease-free survival (hazard ratio [HR], 0.79; 95% CI, 0.66-0.95; P = .01), distant recurrence–free interval (HR, 0.74; 95% CI, 0.56-0.97; P = .03), and breast cancer–free interval (HR, 0.76; 95% CI, 0.60-0.97; P = .02). There was no significant interaction between CLM use and endocrine treatment.
Among women who received tamoxifen only, CLM use did not significantly improve clinical outcomes. CLM use with letrozole monotherapy demonstrated a nonsignificant trend of clinical benefit.
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According to the authors, “the evidence from our observational study warrants consideration of a large, prospective randomized clinical trial to confirm the value of CLM concomitant with endocrine treatment.”
- 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]