A software calculator for assessing cardiovascular risk in breast cancer radiation therapy: development and validation

Objective. To develop and validate a simplified method for rapid assessment of cardiovascular risk in oncology patients with breast cancer (BC), which does notrequire special equipment or the involvement of a cardiologist. Material and methods. The method is based on a systematic analysis of 93 publications (>50.000 patients) and uses the HR coefficient of 1.21 for every 1 Gy of average heart dose, which is based on the central estimate of the range of modern studies: the fundamental study by Darby et al. (2013) — HR=1.074/Gr; Chung et al. (2021) — HR=1.23/Gr; Van den Bogaard et al. (2021) — HR=1.269/Gr; average of the range: (1.165+1.269)÷2=1.217≈1.21. A software calculator has been created. A prospective single-center validation study was conducted at the Voronezh Regional Research and Clinical Oncology Center (n=125 patients, median follow-up of 24 months). Results. The calculator demonstrated excellent prognostic accuracy in the single- center study: AUC=0.89 (95%CI: 0.85—0.93), good calibration (Hosmer—Lemeshow test p = 0.137). Three-level risk stratification showed a cardiac event rate of 2.6% in the low-risk group, 14.7% in the moderate-risk group, and 78.6% in the high-risk group (p<0.001). The time spent by a physician to assess risks using the software calculator is 4.2 minutes. Conclusion. The developed software calculator demonstrated high efficacy in a single-center study. For its widespread implementation in Russian clinical practice, a multicenter study involving oncology institutions from various federal districts is necessary.