Radiation and cardiotoxicity: A retrospective analysis of a midwest population.

Abstract

e12616 Background: The most common female malignancy diagnosed in the US is breast cancer. Early breast cancer therapy is often treated with radiation therapy; one of the unfortunate side effects of radiotherapy in the past has been cardiotoxicity, especially coronary artery disease. Recent usage of dose reduction techniques have helped reduce these effects. Here, we present our analysis of breast cancer patients that received radiation therapy and the likelihood of cardiotoxicity. Methods: An IRB-approved retrospective study was performed utilizing ICD codes to analyze patients diagnosed with biopsy-confirmed breast cancer between January 1, 2014 and December 31, 2017. 478 of 1618 de-identified patients qualified for this study. Statistical analysis was performed with SAS v9.4. Descriptive statistics were computed for all study variables. Continuous variables were described with measures of central tendency (mean, median) and dispersion (range, standard deviation). Categorical variables were summarized as frequencies and percentages. Comparisons between categorical variables were compared with the Chi-Square test (or Fisher’s Exact) where appropriate. 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 is assumed at the p < 0.05 level. Results: Of the 478 eligible patients, heart failure (HF), HF hospitalizations, acute coronary syndrome and overall cardiac events were compared among breast cancer patients. Patients who received radiation experienced HF 6.02% compared to 4.61% without radiation (p = 0.574). HF hospitalization was recorded as 2.27% in radiotherapy compared to 1.23% in non-radiotherapy patients (p = 0.686). Patients who radiation experienced ACS 2.27% of the time as compared to 1.21% in patients who were not treated with radiation. Of note, 9.25% receiving radiation experienced cardiac events compared to 4.24% in patients without radiation (p = 0.068). While results were not statistically significant, the trend of elevated cardiac events in breast cancer patients receiving radiation is noteworthy. Conclusions: Per our study, although statistically insignificant, radiation therapy may result in higher incidence of cardiac events in breast cancer patients. Further large-scale, prospective studies should be performed to confirm the aforementioned trends with respect to survival outcomes in urban and rural populations.