Statin treatment use in diabetic patients with breast cancer: A potential C-reactive protein mediated benefit

173

Background: Statin treatment has not yet been evaluated in relation to breast cancer (BC) prognosis in diabetes mellitus (DM) patients. Reported decreased survival following BC in women with metabolic syndrome, led us to investigate whether specific statin therapy may lead to improved BC survival. Reported associations between elevated C-reactive protein (CRP) levels at the time of diagnosis with worse cancer prognosis, and CRP-lowering properties of statin treatment in non-cancer patients, led us to investigate whether statin use is associated with lower CRP levels at the time of BC diagnosis and with improved BC outcomes.

Methods: All DM patients newly diagnosed with BC between 2003 and 2007 (Roswell Park Cancer Institute) were retrospectively reviewed (n = 225). BC pathology, outcomes, existing comorbidities and drug therapy were documented. Follow up began at BC diagnosis and ended with first confirmed recurrence and/or death, or last date of follow-up. Hazard ratios (HR) and 95% confidence intervals (CI)s representing the association between statins, BC and a defined event were computed with Cox proportional hazards model. CRP plasma levels were determined by enzyme-linked immunosorbent assay in specimens donated at the time of BC diagnosis. A total of 98 study patients, DM+BC, and their matched controls, BC only (n = 196) were analyzed.

Results: After a median follow up of 30 months, patients receiving statins for cholesterol management were found to have better disease-free survival (HR 0.27, 95% CI: 0.10, 0.71, X2 = 7.31, p = 0.06), and lower overall mortality (HR 0.23, 95% CI: 0.08, 0.66, X2 = 7.80, p = 0.05) compared to patients not receiving any cholesterol management medication. CRP levels have ranged between 0.2 and 21 mg/L and clinically relevant levels ( > 3mg/L) were noted in the study group.

Conclusions: This study explored for the first time the association between statin therapy and BC prognosis in DM. We observed improved outcomes in statin-treated patients. While we currently analyze statin therapy in relationship with baseline CRP levels and BC prognosis, our existing findings suggest that statins have the potential to improve BC outcomes potentially through lowering overall inflammation.