In a study reported in the Journal of Clinical Oncology, Signe Borgquist, MD, PhD, of Lund University, Sweden, and colleagues found that use of cholesterol-lowering medication during adjuvant endocrine therapy was associated with a reduced risk of breast cancer recurrence in hormone receptor–positive women in the BIG 1-98 trial.
In the BIG 1-98 trial, conducted from 1998 to 2003, 8,010 postmenopausal women with early-stage, hormone receptor–positive invasive breast cancer were randomized in two schemes to 5 years of tamoxifen vs letrozole or either of these monotherapy treatments or sequential tamoxifen then letrozole or letrozole then tamoxifen. Total cholesterol and use of cholesterol-lowering medication were assessed at study entry and every 6 months for up to 5.5 years.
Serum cholesterol levels decreased during tamoxifen treatment and returned to pre-tamoxifen levels after tamoxifen treatment ended, irrespective of whether tamoxifen was given alone, prior to, or after letrozole. Cholesterol levels were unchanged from baseline levels during letrozole treatment, whether given alone, prior to, or after tamoxifen.
A total of 789 patients (of 5,944 included in the analysis) started cholesterol-lowering medication during endocrine therapy, including 318 in the letrozole monotherapy group, 189 in the sequential tamoxifen/letrozole group, 176 in the letrozole/tamoxifen group, and 106 in the tamoxifen monotherapy group. In multivariate analysis, compared with no use of cholesterol-lowering medication, initiation of medication was associated with significantly better disease-free survival (adjusted hazard ratio [HR] = 0.79, P = .01), breast cancer–free interval (adjusted HR = 0.76, P = .02), and distant recurrence–free interval (adjusted HR = 0.74, P = .03), with no statistically significant interaction between the effects of initiation of cholesterol-lowering medication and assigned endocrine treatment.
A total of 637 patients (of 7,963 included in the analysis) had used cholesterol medication prior to starting study endocrine therapy. In multivariate analysis, history vs no history of exposure to cholesterol medication was associated with significantly better disease-free survival (adjusted HR = 0.82, P = .04) and nonsignificantly better breast cancer–free interval (adjusted HR = 0.83, P =.14) and distant recurrence–free interval (adjusted HR = 0.81, P = .16).
The investigators concluded: “Cholesterol-lowering medication during adjuvant endocrine therapy may have a role in preventing breast cancer recurrence in hormone receptor–positive early-stage breast cancer. We recommend that these observational results be addressed in prospective randomized trials.” ■
Borgquist S, et al: J Clin Oncol 35:1179-1188, 2017.