Post Mastectomy Adjuvant Radiotherapy in Breast Cancer: A Comparison of Cardiac Toxicity in Hypofractionated and Normal Fractionation Protocols

Abstract

Background: Postoperative radiotherapy (RT) for breast cancer is an essential part of adjuvant cancer treatment. RT reduces the risk of local recurrence by 50% and the risk of breast cancer mortality by 16%. Hypo- -fractionated regimens are increasingly being used as they involve fewer treatment sessions and, in terms of tumor control, the effects of conventionally fractionated and hypo-fractionated radiotherapy seem to be comparable. However, the concern for late toxicity especially cardiac toxicity is still under investigation. In our study, we evaluated cardiac toxicity of two radiotherapy fractionation techniques. Patients and methods: This is a prospective randomized clinical trial conducted at clinical oncology department– Menoufia University to assess cardiac toxicity of two fractionation techniques. Between August 2009 and June 2010, 120 patients were randomized into two groups each group 60 patient. Group A: Conventional fractionation radiation (50 Gy/25 fractions/5 weeks, at 2 Gy/fraction). Group B: Hypofractionated radiotherapy (HFR) was 40 Gy in 15 fractions over 3 weeks, at 2.67 Gy per fraction. Echocardiography (ECHO), Electrocardiography (ECG) was performed at base line before chemotherapy, at start of radiotherapy, after 6 months, then annually. Results: A total of 60 patients indicated for postoperative radiotherapy were included in each arm with median follow-up time 60 months range (25-70). Median age is 47 ranges (23-70), (25-68) in group A and B respectively. No significant statistical difference was found between two groups regarding hypertension 25% vs. 21.7% group A and B respectively, also no difference was found between two groups regarding base line and follow-up ECHO and ECG. Patients with left sided breast cancer and/or hypertension showed significant decline in ejection fraction in both groups P value <0.05. In (Group A) hypertensive patients had a median base line EF 63% which declined to 54% at last follow-up in comparison to non-hypertensive patients who had baseline EF of 65% and declined to 60%. In (Group B) hypertensive patients had a median baseline EF 62% which declined to 54% at last follow-up in comparison to non-hypertensive patients who had baseline EF 64% which declined to 59%. Only one patient died to heart failure patient was 70 years old and had history of hypertension and diabetes mellitus. Conclusion: Hypofractionation radiotherapy in the adjuvant setting for treatment of breast cancer has no additional cardiac toxicity in comparison to normal fractionation technique.