Radiation-Induced Coronary Artery Disease in Breast Cancer

Radiation-induced heart disease includes a spectrum of pathology affecting the pericardium, coronary arteries, myocardium, and heart valves. Of these, coronary artery disease may be the most significant cause of mortality from radiation-induced heart disease.

Women who have received adjuvant radiation therapy for left-sided breast cancer have been shown to have an increased incidence of coronary artery disease. The vast majority involve the left anterior descending artery. Indeed, myocardial perfusion defects have been shown to develop in the left anterior descending artery territory following radiation therapy for left-sided breast cancer.

The etiology may be related to damage to capillaries supplying myocytes or to the major epicardial arteries themselves (mimicking the pathological process of atherosclerosis).

Patients with radiation-induced coronary artery disease present in the same way as those without a history of radiation and are usually treated in the same way. Surgical management, however, may be complicated by mediastinal and pericardial fibrosis, concurrent radiation-induced injury to the left internal mammary artery (which is usually used as a graft), and impaired post-operative healing of radiation-damaged tissues.

Modern radiation therapy techniques have reduced the amount of heart that is included in the radiation field, and there is some data to suggest that there may not be an increased risk of mortality related to coronary artery with these newer techniques.

References

• Filopei J, Frishman W. Radiation-Induced Heart Disease. Cardiol Rev. 2012 Feb 6.
• Park CK, Li X, Starr J, Harris EE. Cardiac morbidity and mortality in women with ductal carcinoma in situ of the breast treated with breast conservation therapy. Breast J. 2011 Sep-Oct;17(5):470-6.