LISTEN TO YOUR HEART: CARDIAC CARE AFTER BREAST CANCER

Breast cancer treatments save lives, but sometimes it can leave the heart at risk. Professor Thomas Marwick sheds light on cardiac care for breast cancer survivors, exploring how monitoring and management strategies can protect heart health long after treatment ends.

“I think it’s a very important consideration, and I think we’re recognising increasingly that this is the case. The data is that for women with cured breast cancer their chance of dying from an illness is much more likely with a cardiac illness than their original cancer. And there’s several reasons for this. It seems as though heart failure is the dominant issue here rather than, for example, coronary disease.”

“And there’s several drivers for it. There are probably similar things causing the cancer that cause the heart failure. The toxicity of some treatments is important and then there may be some direct effect of cancer on the cardiovascular system that increases the risk as well.”

What are some common cardiac risks or complications associated with breast cancer therapies?

“The way I look at this is really at the time of treatment and then afterwards. So, at the time of treatment anthracyclines are a group of cancer-treating chemotherapy that have been used for a long time and are decreasingly used in breast cancer, fortunately, but still required in some situations.”

“And then there’s a number of other molecules such as trastuzumab, that are used for this as well. Both of them can have adverse effects on cardiac function. So, we monitor the heart very carefully during cancer treatment and it may be necessary to initiate some sort of protection. And then after cancer treatment people have got some legacy of their cancer or their treatment that goes on for years.”

“And then on top of that, various things happen in people’s lives. They gain weight, they get diabetes, they get high blood pressure. All of those things are drivers of heart failure, and so we think that it’s important to have some sort of ongoing surveillance for cardiac problems in addition to the normal cardiac prevention strategies of controlling blood pressure and cholesterol and those kinds of things.”

Are patients typically monitored during and post-treatment?

“It depends on the nature of therapy. If either of those treatments that I mentioned anthracyclines or trastuzumab are being used, then usually an assessment of cardiac function, most commonly an echocardiogram, an ultrasound test to the heart, is done at baseline and then with some frequency during follow up.”

“Different oncologists and different cardiology groups use slightly different strategies for this, but essentially the cardiac function should be checked in that year of cancer treatment. We would say four times. Obviously, it depends on the circumstance and the level of risk, and then afterwards, I think there’s a need for the patient or the person who’s being cured from breast cancer to be followed up by their GP in the knowledge of what they’ve been treated with, because that will impact on the threshold of monitoring.”

“But certainly, awareness on the part of the patients is really important here, so that people who, for example, are developing exercise intolerance with the passage of years, that often the response is I’m just getting older, or I’ve put on a bit of weight, so I’m getting a bit short of breath.”

“You can’t afford to make that sort of decision in the context of having treated breast cancer. So, awareness on the part of the patient and the doctor. There is a lot of controversy at the moment about whether people should have ongoing monitoring with echocardiography. I think it really depends on the risk, and we have worked on a risk score to try and understand this a bit more, but it’s work that needs to be tailored to the patient.”

Are there challenges in balancing effective cancer treatment whilst needing to protect cardiac function for certain patients?

“I think that is often a concern, but there’s protection that we would use to begin with are a group of drugs called neurohormonal protection. That’s to say ACE inhibitors, angiotensin receptor blockers and beta blockers. And they don’t really have an effect on cancer. There are some treatments, there’s one particular one called Dexrazoxane that has been used in people having anthracyclines.”

“The concern with that has always been that it’s detrimental to the effect of the anthracycline. I think the evidence is not pointing that way from my reading of it. But that is a concern. But in general, I think it’s reasonable to understand that these are separate things and the presence of the cancer shouldn’t inhibit the desire to protect the heart.”

“And of course, the thing that you most want to avoid is concern about the heart interfering with the cancer treatment itself. And that’s something that you know should occur very rarely indeed.”

Are there emerging technologies or approaches that could improve early detection or prevent cardiac issues from occurring in the first place?

“Yeah, we are really interested in that. One whole area that’s important here is exercise. Interestingly, I think this is most important in relation to the effect of chemotherapy on the heart. Because chemotherapy obviously involves lots of things, including blood vessels and muscles.”

“And we think that some of the problem here relates to reduction of activity and, therefore the reduction of the small vessels that the heart ejects into, which puts an increased load on the heart. And there is evidence that by exercise training during cancer, you’re able to avoid that process. So that’s important in terms of detection.”

“There are some new technologies that are coming through. Obviously, there’s a challenge of doing a repeated echocardiogram, and it may be possible to get similar information or at least screening information from an ECG not the sort of things that we measure on an electrocardiogram, but things that the computer can detect. And we are working very actively in that space. So, it’s not really for prime time, but it may be part of the future of surveillance in this situation.”

And are there things that patients can do to reduce the likelihood of cardiac events occurring during their breast cancer treatment?

“I think during treatment, maintaining activity is important and some centres, particularly overseas, are offering essentially a rehabilitation or a prehab process, if you like to try and stop people losing that functional capacity. I think attendance to controlling risk factors is really important. We track various measures of cardiac function, and I’ll never forget a particular patient I saw, while I was still working in America, who seemed to be doing fine and then came in and these measures were really seriously awry.”

“And I spoke to her about what was going on, and in fact, her youngest child had just left the family home to go to university, which of course, is a big deal. They travel right across the country, and her blood pressure was up, and it’s just an illustration about how standard risk factors impact cardiac function and on top of the injury of chemotherapy, that can be very detrimental. So, attending to the humdrum routine, and controlling one’s blood pressure is really important.”

And so, what advice would you give clinicians and patients about integrating cardiac care into survivorship planning?

“Look, I think that this is a very important area in multiple cancers. Breast cancer particularly but also haematological malignancies because they often occur in older people. I think the person at the centre of this is the primary care physician or general practitioner. They need to have knowledge of the nature of chemotherapy and the dose of chemotherapy. And although that sounds trivial, I can tell you as a researcher in this space for a number of years, I find that really hard to obtain.”

“And yet that is very influential in deciding how intensely to follow the patient up. So that’s important. And then if there are any areas of concern or any areas where risk factors are not being controlled, then seeking help early in the piece is very worthwhile.”

“So, there are a group of cardiologists now, an increasing group who are being trained in cardio-oncology, and this interface between cardiology and cancer. And that’s important and those folk bring expertise to this area. That will hopefully stop, the cancer patient of today, turning into the heart failure or cardiac patient of tomorrow.”

And so, what are your hopes for the future in this space?

“My hopes are very much related to the surveillance of this as a cardiologist, whenever I see a patient coming into the hospital with heart failure. I always feel this is an avoidable problem. This is a detectable problem early and people can get into really deep water and it’s avoidable. So, to me, the issue is about surveillance.”

“It’s about identifying people who are at risk and then maintaining some means of knowing when things are going awry and our work is very much focused on producing a kind of strategy of understanding clinical risk and then layering on top of it the artificial intelligence and ECG components, and then the echogram to identify people where the cardiac function is going off.”

“And then moving with cardiac protective medications to stop the situation getting worse and yes, I think we’re on the path to that, but it’s a lot to change and changing clinical practice is not easy. So there’s still work to be done.”