RESUMEN
Cardiovascular damage after Radiotherapy of left chest wall for left breast cancer is a potential fear, therefore studing both the possible causes of radiation-induced heart damage and preventive measures are crucial issues in radiation therapy of breast cancer. The present study investigates noninvasively the possible acute and chronic ECG changes and their incidences after Radiotherapy in patients with left sided breast cancer who have received 6-8 courses of Anthracycline based chemotherapy following mastectomy. 56 patients with breast cancer [invasive ductal carcinoma] who had been undergone modified radical mastectomy, adjuvant Anthracycline based chemotherapy, and left sided chest wall electron therapy with direct field, have been evaluated. All patients investigated with physical examination and standard 12 leads ECG before, and immediately after completion of radiation therapy, and 6 months afterward. New electrocardiographic changes after therapy were seen in 3 patients [5.35%] and reduced to 2 cases [3.57%] after 6 months. there was no significant difference in T wave findings before and after radiation therapy[P=0.521].Also there wasn't any correlation between stage of cancer and any changes in ECG findings after radiation therapy [P=0.56]. There were no clinical cardiac symptoms or signs after Radiotherapy. Most affected leads in ECG were V1-V4 and the main abnormality was Inverted T wave. This findings suggest that the most acute and chronic electrocardiographic effect of irradiation on heart is repolarization abnormality. This study suggests that there are no significant ECG changes after Radiotherapy of left chest wall by electron beam in patients with left sided breast cancer who has received Anthracycline based chemotherapy following mastectomy. Also Radiotherapy by electron doesn't induce any clinical cardiac symptoms and signs in these patients. Therefore, we recommend using electron beam for Radiotherapy of patients with left sided breast cancer after radical mastectomy if Anthracycline based chemotherapy, has been administered