My heart disease may be related to radiation I had for breast cancer. How dangerous is this?

I just had a heart cath which showed no blockage; yet the apex of my heart is not getting blood flow. My doc thinks it’s radiation caused damage from my breast cancer treatments about 8 years ago. How dangerous is this and do I have an increased risk of stroke and heart attack? Can the damage continue to spread?

Submitted by Sue from Washington on 01/11/2014

by Deborah E. Meyers, MD

Dear Sue,

First of all congratulations at getting through your treatment for breast cancer. It is also great news about your catheter study that no blockages were found. All of that is very reassuring.

There is quite a lot that your letter does not tell me that I would need to know to give you the complete answer. For example, what type of test showed that the apex of your heart is not getting adequate blood flow? My suspicion is that you may have had a nuclear imaging test that showed this as these tests are pretty commonly performed. These tests are notorious for showing attenuation artifacts which can look the same as “no blood flow” in that region of the heart in women. Some of this depends on your breast size or body habitus. You also do not mention if you ever had chemotherapy which can have some cardiac effects as well.

If this scarring was shown on a PET scan or a cardiac MRI I would be a bit more convinced. Finally, what is the function of this area of the heart? Is the muscle moving and contributing to the overall heart pumping normally? This would best be seen on echocardiography or cardiac MRI? If everything is moving properly again I would be less concerned.

Your cardiologist is quite right however that radiation can cause some cardiac damage. Typically this is more pronounced when the left breast is radiated and the radiation is closer to the heart.

I would not expect it to spread at this late date.

If your coronary arteries are clear at this stage then your risks of coronary artery disease are probably about the same as anyone else with your age, with your risk factors, and your family history. If your heart muscle is working well and you have a normal heart muscle function then your radiation therapy should not pose a big risk for strokes either.

I would encourage you to discuss all of your concerns with your cardiologist who will know the specifics of your situation and should be able to answer your questions with all the facts at hand.