Cholesterol Drugs Improve Breast Cancer Prognosis in Women with Diabetes Mellitus

Study objective: To evaluate the impact of Cholesterol management on breast cancer recurrence and survival (CHOLBRES) in diabetic women with breast cancer. Design: Cholbres study included all incident breast cancer cases with pre-existing diabetes mellitus diagnosed with cancer between 01/01/2003-12/31/2007. Clinical characteristics, outcomes, and pharmacotherapy were abstracted from medical records or hospital-developed databases. The follow-up, with a median of 31 months, began at breast cancer diagnosis and ended at first recurrence, death, or date of last contact. Patients: All diabetes mellitus women with incident breast cancer were identified (n=269); of these 208 met the inclusion criteria and were used for analysis. Methods: The association between self-reported cholesterol-lowering medications and breast cancer outcomes was evaluated with multivariate Cox proportional hazards models. Main results: Women taking cholesterol-lowering drugs were found to have fewer recurrences (HR=0.54, 95% CI: 0.24 to 1.18, p=0.12), improved overall survival (HR=0.48, 95% CI: 0.27 to 0.86, p=0.01), and better disease-free survival (HR=0.65, 95% CI: 0.35 to 1.21, p=0.17) than women who did not take any cholesterol-lowering medication. Cholesterol management employing statins as a mono-therapy was associated with better overall survival (HR=0.42, 95% CI: 0.21 to 0.84, p=0.08) and slightly improved disease-free survival (HR=0.49, 95% CI: 0.23 to 1.04, p=0.24). Conclusion: Our findings demonstrate that cholesterol-lowering therapy significantly improves breast cancer prognosis in women with diabetes mellitus. Though larger studies are needed to confirm this potential added benefit, efforts to ensure that women with breast cancer and diabetes receive guideline-appropriate cholesterol-lowering medications should have significant impact on breast cancer outcomes.