Patients with early-stage, hormone-receptor positive breast cancer who used cholesterol-lowering medication at baseline of a long-term randomized study had more beneficial tumor characteristics and improved outcomes, compared with nonusers.
The findings come from an observation study of a randomized, phase III, double-blind trial conducted by the Breast International Group (BIG) known as BIG 1-98, which enrolled 8,010 postmenopausal women with early-stage, hormone receptor–positive invasive breast cancer from 1998 to 2003. As reported online in the Feb. 13, 2017 issue of the Journal of Clinical Oncology, researchers measured systemic levels of total cholesterol and use of cholesterol-lowering medication at study entry and every 6 months up to 5.5 years. Endpoints of interest were disease-free survival, breast cancer–free interval, and distant recurrence–free interval.
Of the 789 patients who initiated cholesterol-lowering medication during endocrine therapy, most were assigned to letrozole monotherapy (318), followed by sequential tamoxifen-letrozole (189), letrozole-tamoxifen (176), and tamoxifen monotherapy (106).
The results showed that initiation of cholesterol-lowering medication during endocrine therapy was related to improved disease-free survival (hazard ratio 0.79; P = .01), breast cancer–free interval (HR, 0.76; P = .02), and distant recurrence–free interval (HR, 0.74; P = .03).
“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 of breast cancer,” corresponding author Signe Borgquist, MD, PhD, of the division of oncology and pathology at Lund University, Sweden, and her associates concluded. “Further elucidation of the effect upon outcome of the clinical interaction between CLM and endocrine agents – both widely used by patients with breast cancer – will provide exclusive insight to future trial designs.”
The BIG 1-98 trial was supported by Novartis and coordinated by the International Breast Cancer Study Group (IBCSG). Of the 17 study authors, 7 reported having relevant financial disclosures.