Can intensity modulated radiation therapy reduce cardiac dose in left-sided breast patients?

Purpose: In recent years interest has grown in the investigation and clinical application of intensity modulated radiation therapy (IMRT) for adjuvant treatment of early stage breast cancer. A review of the current literature was conducted to establish if IMRT can reduce doses delivered to the heart and potentially minimise the likelihood of cardiac toxicities for early stage left-sided breast cancer patients. Methods: A literature review was undertaken to identify recent studies (1999–2009) that compared IMRT with three-dimensional conformal radiation therapy (3D CRT) techniques for left-sided breast patients. Results: Based on the five reviewed articles, IMRT reduces the cardiac volume treated to high doses; however this is at the expense of an increase in the volume treated to low/intermediate doses. The maximum dose to the coronary arteries and left ventricle can be reduced with IMRT. Using radiobiological modelling some studies found a reduced risk of normal tissue complication probability (NTCP) for cardiac mortality with IMRT. Conclusion: The evidence provided in this review encourages the use of IMRT approaches in the treatment of early stage left-sided breast cancer in order to minimise morbidity specifically to cardiac tissue. However, in order to ensure optimal use of resources, thought needs to be given as to which women will benefit most from complex treatment approaches.