Does prophylactic breast irradiation in patients with prostate cancer influence cardiac toxicity?

age without cardiac morbidity. When using the CT-based beam, 10% of the younger patients and 15% of the older patients would receive approximately 50% of the prescription dose to a part of the anterior myocardial wall of the left ventricle and the small vessels in this region ( Fig. 1 ). When using the clinically determined beam, which is often used in practice, an additional 12.5% of the patients would be exposed to a dose comparable to that from the CT-based beam. This preliminary analysis that was performed in randomly selected individuals who had CT examinations for various medical reasons suggests that CT-based approaches for PMRT might benefi t approximately 20% – 28% of patients because it can reduce the radiation dose to the heart compared with non-CT – based approaches. Data suggest that doses as low as 4 – 5 Gy might contribute to cardiac toxicity and are largely in agreement with radiobiologic data on the pathogenesis of radiation-induced heart disease ( 7 ). The endothelial lining of blood vessels might be particularly vulnerable to radiation; exposure may result in slow progressive functional and structural alterations. Even partial exposure of the heart to radiation might contribute to long-term damage after several years. Despite the fact that a causal relationship between the relatively low radiation doses from PMRT and cardiac morbidity or mortality has not been proven, it is prudent to minimize all factors that might contribute to noncancer mortality in these patients. Future epidemiologic studies on the cardiac side effects of androgen suppression should include data on the use of PMRT.