A Prospective Study on the Role of Strain Echocardiography in Detecting Early Radiation-induced Cardiotoxicity in Left-sided Breast Cancer Patients.

Introduction: Breast cancer radiotherapy has a clear benefit for both long-term survival and local control rate. However, healthy surrounding normal tissues, including the heart and lungs, can negatively impact a patient's quality of life.

Objective: This study aims to clarify the contribution of echocardiography with Global Longitudinal Strain to early radiation-induced cardiotoxicity detection.

Methods: The sample of our prospective study consists of 25 patients with early-stage left-sided breast cancer. 2D strain echo was estimated on all patients before and one year after radiotherapy. For the control of the normality of the condition, the Shapiro-Wilk test and the study of graphical representation of the «Box Plot» were used. For the comparative analysis of average values of a continuous variable and between two-time points, the Wilcoxon test was used. SPSS 25 software was used for the statistical processing of the data.

Results: Mean Global Longitudinal Strain value before and one year after radiotherapy was -20.2% and -21.2%, respectively. In half of the cases, the values ranged from -19.65% to -22.70% before radiotherapy and between -18.8% and -22.25% after radiotherapy. The non-parametric Wilcoxon test indicated no statistically significant difference before and after radiotherapy (Ζ =0.902, p = 0.367).

Conclusion: Our study did not detect any significant difference in the mean Global Longitudinal Strain pre and post-radiotherapy. However, early radiation-induced cardiotoxicity diagnosis should be a priority throughout the treatment process, requiring further studies with a larger sample size and a longer follow-up to find valuable tools to minimize the side effects of therapeutic manipulations.