ACE inhibitors and angiotensin receptor blockers use and breast cancer outcomes in patients treated with neoadjuvant systemic chemotherapy.

Abstract

537 Background: There is a growing body of evidence to suggest that ACE inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) might have anti-tumor properties. We investigated whether the use of ACEI/ARBs during chemotherapy affects the clinical outcomes of breast cancer patients receiving taxane and anthracycline-based neoadjuvant chemotherapy. Methods: We included in this analysis 1449 patients with diagnosis of invasive primary breast cancer diagnosed at the MD Anderson Cancer Center between 1995 and 2007 who underwent neoadjuvant chemotherapy. Of them, 160 (11%) patients were identified by review of their medical record, as ACEI/ARBs users. We compared pathologic complete response (pCR) rates, relapse-free survival (RFS), disease-specific survival (DSS) and overall survival (OS) between ACEI/ARB users and non-users. pCR was defined as no evidence of invasive carcinoma in the breast and axillary lymph nodes at the time of surgery. Descriptive statistics and Cox proportional hazards model were used in the analyses. Results: There was no difference in the pCR rates between ACEI/ARB users (16%) versus non-users (18.1%) (p=0.50). After adjustment for important demographic and clinical characteristics, no significant differences between ACEI/ARB users and nonusers were observed in RFS (HR=0.81; 95% CI=0.54-1.21; P=0.30), DSS (HR=0.83; 95% CI=0.52-1.31; P=0.42), or OS (HR=0.91; 95% CI =0.61-1.37; P=0.66). In a subgroup analysis among ARB users, the 5-year RFS was 82% vs 71% in ACEI/ARB non-users (P=0.03). In the multivariable analysis, ARB use was also associated with a decreased risk of recurrence (HR=0.35; 95% CI=0.14-0.86; P=0.02). However, no statistically significant differences in DSS or OS were seen. Conclusions: No differences in pCR and survival outcomes were seen between ACEI/ARB users and non-users among breast cancer patients receiving neoadjuvant chemotherapy. ARB use may be associated with improved RFS. Further research is needed to validate this finding.