Evaluation of cardiac function in patients undergoing adjuvant radiotherapy to the left breast

Full text: Introduction: In Brazil, 73,610 new cases of breast cancer were estimated for the year 2023. Radiotherapy is a medical modality that uses ionizing radiation beams to treat diseases, especially in cases of breast cancer. However, healthy organs surrounding the breast region may receive radiation, suffering deleterious effects. Radiotherapy-induced cardiotoxicity is one of the most significant adverse effects of oncologic treatment, due to the fact that the anterior wall of the cardiac area is very close to the internal limit of the irradiation fields. The literature presents few data on pre- and post-radiotherapy cardiac function in patients with left breast cancer. This study illustrates the relevance of radiation dose on cardiac function in patients treated for left breast cancer, aiming at irradiation techniques that minimize exposure to normal cardiac and pulmonary areas, reducing the toxicity of therapy. Objectives: To evaluate cardiac function in patients undergoing left breast radiotherapy using two different techniques: conventional two-dimensional radiotherapy and conformal three-dimensional radiotherapy. Methods: A prospective, randomized study was conducted in patients undergoing adjuvant radiotherapy for left breast cancer. To assess cardiac function, myocardial scintigraphies were performed before treatment and three months after. The parameters of analysis were ejection fraction and global left ventricular function, both indicated in nuclear medicine examination reports. Results: The survey comprised 12 female patients. The average age was 57 years. About 75% of the patients already had some comorbidity such as hypertension, diabetes, arrhythmia, hypothyroidism or obesity. Three-dimensional radiotherapy was used in 25% of the patients and two-dimensional radiotherapy was used in 75%. No significant change in ejection fraction or global left ventricular function was observed after radiotherapy. Conclusion: There was no change in cardiac function with clinical repercussion in patients undergoing radiotherapy with conventional two-dimensional and conformal three-dimensional treatment techniques. However, given the complexity and relevance of the study, it is suggested to continue the research to have a more quantitative sample of patients with different clinical stages. (author)