Association of statin use on survival outcomes of patients with early-stage HER2-positive breast cancer in the APHINITY trial

Purpose There is evidence that statins might improve the outcome of patients with breast cancer. The role of statins in patients with early HER2-positive breast cancer is unknown. Therefore, we explored the association between statin use and survival outcomes in early HER2-positive breast cancer patients in the phase III APHINITY trial (adjuvant pertuzumab/ trastuzumab). Methods All patients (intent-to-treat population, n=4804) were included (6.2 years median follow-up database). The primary objective was to investigate the association of statin use on invasive disease-free survival (IDFS), distant relapse-free interval (DRFI), and overall survival (OS). Patients who received statins at baseline, or started statins within 1 year from randomization were considered statin users. Survival curves were estimated using the Kaplan–Meier method. We used a Cox proportional hazards model for multivariate analysis. Results Overall, 423 (8.8%) patients were classifed as statin users. They were older, more often postmenopausal, had a higher body mass index, more often diabetes, hypertension, coronary heart disease and hyperlipidemia, had smaller sized tumors, were treated more often with breast conserving surgery, and less often with anthracycline-containing regimens. Overall, 508 IDFS events (12.8% among statin users and 10.4% among non-statin users) and 272 deaths (8.5% and 5.4%, respectively) occurred. In multivariate analysis, statin use was not associated with IDFS (HR, 1.11; 95% CI, 0.80–1.52), DRFI (HR, 1.21; 95% CI, 0.81–1.81) nor OS (HR, 1.16; 95% CI, 0.78–1.73). Conclusion In APHINITY, statin use was not associated with improved survival outcomes. These results must be interpreted with caution due to the exploratory nature of the analysis and the associated limitations.