Prediagnostic statin exposure positively influences breast cancer-specific survival
Prediagnostic statin exposure appears to be associated with a significant reduction in breast cancer-specific mortality, with the survival benefit being more pronounced in women with oestrogen receptor (ER)-positive tumours, according to a study.
The study included 6,314 women with stages I to III breast cancer, including 2,082 with prediagnostic statin exposure (median age 71 years). In the group with no prediagnostic statin use (n=4,232), the median age was 67 years.
Prediagnostic statin use was analysed in relation to lymph node status and breast cancer-specific and all-cause mortality.
There was no association between prediagnostic statin use and lymph node negative status at diagnosis (adjusted risk ratio [RR], 1.01; 95 percent CI, 0.95 to 1.08).
However, prediagnostic statin users had particularly lower all-cause mortality (adjusted hazard ratio [HR], 0.78; 0.69 to 0.89) and breast cancer-specific mortality (adjusted HR, 0.81; 0.68 to 0.96) compared with prediagnostic nonusers.
The protective effect of prediagnostic statin exposure on cancer-specific mortality was greatest in statin-users with ER-positive tumours (adjusted HR, 0.69; 0.55 to 0.85).
Researchers explained that the association between prediagnostic statin and reduced breast cancer-specific mortality and all-cause mortality in patients with stages I to III disease, particularly among those with ER-positive breast cancer, may be explained by cholesterol-lowering effect of statins.
Statins reduce the level of cholesterol in the circulation, and, subsequently, the level of 27-hydroxycholesterol (27HC)—a cholesterol metabolite and a selective ER receptor modulator (SERM) capable of promoting proliferation in ER-positive cells. So, it is possible that the decrease in 27HC may reduce the proliferation of ER-positive tumour cells. [Climacteric J Int Menopause Soc 2014;17:60–65; Oncotarget 2016;5:59640–59651]
Additional studies are needed to further explore the complex interplay between statin exposure, tumour 3-hydroxy-3-methylglutaryl coenzyme-A reductase expression and breast cancer outcomes, researchers said.