Survival outcomes in post-menopausal patients with underlying cardiovascular disease receiving endocrine therapy for the treatment of breast cancer.

e12549 Background: Breast cancer remains the number one threat to women’s health while cardiovascular disease (CVD) continues to be the leading cause of mortality in women worldwide. Adjuvant therapy with endocrine therapies (selective estrogen receptor modulators (SERM), estrogen receptor blockers (ERB), and aromatase inhibitors (AI) although known to reduce the recurrence of breast cancer in hormone receptor positive breast cancer patients, raise a concern for increased risk of cardiovascular disease. Our study aims to examine breast cancer survival outcomes on patients receiving endocrine therapy who have pre-existing CVD including heart failure. Methods: An institutional database of 478 patients with histologically confirmed hormone receptor positive breast cancer diagnosed between 01/01/2014 to 12/31/2017 was reviewed after IRB approval. Preexisting CVD included coronary artery disease (CAD), history of myocardial infarction (MI), and prior diagnosis of heart failure (HF). Patients were divided in groups depending on treatment with endocrine therapy and underlying CVD. Statistical analysis was performed with SAS v9.4. software. Survival curves were estimated using Kaplan-Meier methodology and analyzed with a log rank test. Predictors of survival were assessed with Cox proportional hazards regression analyses. All significance was assumed at the p < 0.05 level. Results: Of 478 patients who met the inclusion criteria, 336 (70%) patients were postmenopausal. Out of those 336 patients, 62.2 % (n = 209) received at least one of the endocrine therapies consisting of AI, SERM or an ERB. Of these patients, 2.9 % (n = 6), 9.6% (n = 20) and 5.7% (n = 12) had a significant medical history of underlying MI, HF and CAD, respectively. Survival analysis was performed on 80% (n = 168) patients of the 209 patients with 2.3% (n = 4), 8.9% (n = 15) and 5.2% (n = 11) with underlying MI, HF and CAD respectively. There was no statistically significant difference in survival in these postmenopausal women who received endocrine therapy despite preexisting cardiovascular disease (HR 3; 95% CI, 0.5-16, p > 0.05). Conclusions: A commonly known toxicity related to the adjuvant therapy including endocrine therapy of breast cancer is cardiac toxicity. Patients with history of CVD might be at the highest risk for such toxicity. Our finding is reassuring that endocrine therapy in patients with preexisting CVD including heart failure did not result in reduced survival for our patient cohort.