Background: Radiation to some parts of the heart is unavoidable in the therapeutic course of primary tumors in many kinds of cancer, including breast cancer. The aim of this study was to assess the frequency of acute and subacute cardiac complications following radiotherapy in patients with left breast cancer.

Methods: In this study, we enrolled 53 patients with left breast cancer who underwent mastectomy or lumpectomy between September 2005 and September 2006 in Imam Khomeini Hospital Complex, and subsequently underwent chemotherapy with anthracyclines (<450mg/m²) and Endoxan plus taxane/fFluorouracil followed by radiotherapy. In all patients, electrocardiography and echocardiography were performed before initiation of radiotherapy, immediately after radiotherapy and again three and six months later to check for radiotherapy-induced cardiac complications such as pericardial effusion, valvular lesions, left ventricular dysfunction, conduction system disturbances and other variables.

Results: Thirty-nine patients completed the follow-up period. Among these, 10 (25.6%) patients experienced cardiac complications following radiotherapy. Among these, mild pericardial effusion in seven (53.85%) patients, mild mitral regurgitation in three cases (23.08%) and Right Bundle Branch Block (RBBB) in two cases (15.38%) were the most common complications. We found no correlation between cardiac complication and tumor dose, dose fraction and type of chemotherapy protocol. We noted no cases of new or more serious complications, such as cardiomyopathies or coronary artery disease, nor any changes in ejection fraction by the end of the follow-up period.

Conclusion: In patients with left breast cancer, acute and subacute cardiac complications following radiotherapy are not serious and have no clinical significance. Further studies are needed for more assessments in this area.