Derangements in Coronary Calcium Score and Left Ventricular Global Longitudinal Strain in Patients Post Left Breast Radiotherapy

Abstract Background Radiotherapy is a common treatment for breast cancer, with unintended long-term CV consequences; and no consensus on adequate CV screening methods to prevent future events. We aimed to assess the use of coronary artery calcium (CAC) and left ventricular global longitudinal strain (GLS) to identify those at risk for CVD due to radiotherapy. Methods Using data from an urban cancer registry, we enrolled 17 women (mean age 62 years) with left-sided breast cancer from 1999-2003, treated with radiotherapy. Agatston CAC score was measured by CT scan; and GLS by echocardiography. Logistic regression was used to compare study CAC scores with historical controls using age- and race-matched (Multi-Ethnic Study of Atherosclerosis) MESA CAC calculator [derived from MESA cohort from 6 US communities, free of clinical CVD at baseline (2000-2002) https://www.mesa-nhlbi.org ]; and GLS with historical controls from prior meta-analysis with defined normal GLS values ( Yingchoncharoen et al). Results The Hosmer-Lemeshow goodness of fit test reported a significant lack of fit (p < 0.02) compared with the expected probability of non-zero CAC in the historical controls from MESA. The mean GLS of -20.6% (95% CI: -21.50%, -19.79%), and was not statistically different when compared with the average of the historical controls. However, there was a significant difference of GLS compared to the meta-analysis using a one-sample T test with P=0.03. Conclusion We found that women post left sided breast radiotherapy had higher CAC presence without significant difference in mean GLS, compared with historical controls from the MESA database and prior GLS meta-analysis.