Cholesterol, Cholesterol-Lowering Medication Use, and Breast Cancer Outcome I the BIG 1-98 Study

Authors: Borgquist, S. et. al.

Source: J Clin Oncol DOI: 10.1200/JCO.2016.70.3116

ascopubs.org/doi/abs/10.1200/JCO.2016.70.3116

The actions of CLMs in estrogen receptor-positive breast cancer are being studied.  These medications block an enzyme in breast cancer cells that is linked to prognosis.  CLMs also appear to reduce cellular production of estrogen.  Finally, CLMs limit the growth of estrogen receptor-positive breast cancer cells by altering the receptors directly.  The group posed the question: do CLM’s in combination with endocrine therapy improve breast cancer outcomes?

Over 8,000 postmenopausal women with early stage, estrogen receptor-positive breast cancer were part of a long-term trial that compared outcomes with tamoxifen alone, tamoxifen with letrozole and letrozole alone.  These women were sorted into two different groups: those who had no exposure to CLMs prior to the start of the study and those who had used CLMs in the past or were current users. 

Women who had used CLMs had higher disease-free survival, lower rates of breast cancer recurrence and lower rates of distant disease recurrence compared to women who had no exposure to CLMs.  It was noted that more women on CLMs were taking letrozole as opposed to tamoxifen.  The women taking CLMs also had more favorable disease characteristics (smaller tumor size, fewer lymph nodes involved).

This study confirmed the theory that CLMs may improve outcomes of estrogen receptor-positive breast cancer.  More studies examining this possible link are needed.