Is dobutamine stress echocardiography a good screening tool for coronary artery disease in breast cancer patients that underwent treatment with radiotherapy?

Abstract INTRODUCTION Accelerated atherosclerosis has been described in breast cancer patients receiving cardiac exposure from adjuvant radiotherapy (RT). As a result of multidisciplinary care, breast cancer cure rates have improved in recent decades. Therefore, evaluating radiation-induced heart disease (RIHD), especially coronary artery disease (CAD), is essential. The 2022 cardio-oncology European Society of Cardiology (ESC) guidelines recommend screening patients 5 to 10 years after RT for CAD according to cardiovascular risk factors. This screening is generally recommended with exercise stress echocardiography since it can assess the physiological functional performance. Until now, it is unknown if dobutamine stress echocardiography (DSE) is an equal screening tool and if it can predict major adverse cardiovascular events (MACE) (myocardial infarction, stroke, cardiac death, revascularization). PURPOSE Evaluate if DSE is an adequate tool to stratify and predict MACE in post-radiotherapy patients. Methods A retrospective, descriptive cohort study was conducted. Patients who had chest RT for breast cancer and underwent DSE from 2000 to 2022 were included. A bivariate analysis, including Kruskal Wallis and Pearson Chi-Squared test, was done to identify variables associated with a positive DSE. A multivariable Cox Model for MACE and a time-to-event curve for MACE were also performed. Results We identified 163 patients that underwent DSE after a median time of 5.8 years from the end of RT. The median age was 74 years, 98.2% were female, 50% had left and 45% right breast cancer, 81% had hypertension, 41% diabetes mellitus, 71% dyslipidemia, 34% were smokers, and 19% had a prior myocardial infarction. The average dose of photon RT to the chest was 55Gy in the cohort, and 40% received chemotherapy before RT. Patients were divided into two groups: positive and negative DSE. A positive DSE was seen in 19.6%. The median (Q1, Q3) regional wall motion abnormalities (RWMA) of patients with a positive DSE was 1 (1, 1.015) at baseline and 1.280 (1.190, 1.520) at peak stress, and for a negative DSE, was 1 (1, 1) at baseline and peak stress. 88.2% of negative DSE and 87.5% of positive DSE achieved the target heart rate of 85%. HTN, dyslipidemia, and prior MI were significantly associated with a positive DSE (p <0.023). The cumulative incidence of MACE was higher in the group of positive DSE (p<0.001), even after adjusting for hypertension, diabetes mellitus, dyslipidemia, smoking, and prior myocardial infarction, with a hazard ratio of 2.500 (1.51 – 4.13) and a p< 0.001. Similar results were observed regardless of RT laterality. Conclusions In breast cancer survivors that received adjuvant radiotherapy as part of multidisciplinary care, a positive DSE was an independent predictor of MACE compared to a negative result. These results support the usefulness of dobutamine stress echocardiography as a screening tool in breast cancer survivors.Kaplan-Meier Curve for MACE