Room: Exhibit Hall | Forum 6
Purpose: The aim of this study was to evaluate the use of coronary CT angiography to detect pre-clinical coronary artery disease (CAD) after left breast irradiation and to correlate extension, severity and location of coronary lesions with the dose to heart.
Methods: 13 left-sided breast cancer patients that had completed RT three years ago, with mean doses (Dmean) to heart from 5 to 20 Gy were selected. None had received cardio toxic chemotherapy. A control group of non-oncologic 19 women matched in age and CAD risk factors was used for comparison. For these two groups a ECG-gated prospective coronary CT angiography (CTA) with a 256-slice CT scan (Philips Brilliance iCT) was performed. Findings on CTA using standardized reporting were recorded. Patient age, cardiovascular risk factors, treatment technique and RT heart dosimetric indexes (V30, V25, Dmean and D2) were collected. The CTA was registered with the planning CT, mean dose to coronary lesions and Left Anterior Descending Coronary Artery (LAD)+1cm margin were calculated. Differences between the study and control groups and correlations between CTA findings and heart dosimetric indexes were evaluated.
Results: This study shows that this series of irradiated patients have a higher extension and severity of asymptomatic CAD than the control group, with a clear tendency to significance (p=0.11).There is no correlation of CAD with Dmean, while V25 and V30 correlate with all studied indexes but the spatial location of the lesions does not correspond to the highest doses on the LAD.
Conclusion: The results of this cross-sectional study are a proof of concept that CTA is useful to detect CAD after left breast irradiation in asymptomatic patients. The preliminary results show that the number and severity of lesions correlate with heart V25 and V30. However, more work is needed to define the V25-V30 thresholds to indicate CTA.
Tolerance Doses, Heart, Radiation Therapy