COMMENTARY

What Cardiologists and Oncologists Need to Know About Cancer Treatment Cardiotoxicity

Dr Sukh Nijjer

Disclosures

April 12, 2021

Dr Sukh Nijjer and guests discuss new guidelines on what cardiologists and oncologists need to know about heart risks for cancer patients.

This transcript has been edited for clarity.

Dr Sukh Nijjer

Hello, and welcome to another Medscape UK video. Today I'm joined by two excellent colleagues working here in London, and they're going to be talking about a very complex area in the growing field of cardio-oncology.

I'm joined by Dr Susannah Stanway and Dr Arjun Ghosh. Dr Stanway is a medical oncologist, who has done extensive work in the use of cancer treatments and the disparities of care around the world.

Dr Arjun Ghosh is a cardiologist with specialist interest in cardio-oncology, and has been working very hard in this rapidly growing field. He has developed some new guidelines which will alter the way we perform cardiac monitoring in patients undergoing treatment for cancer.

Many of you will know that advanced cancer therapies can have a negative impact on cardiac function. And most of our patients who have these advanced therapies do require regular monitoring of their heart function using various technologies: echocardiography, MIBI scans [myocardial perfusion imaging], cardiac MRIs, whatever is available.

Here in the United Kingdom, it's very common to do serial measurements using echocardiography and Dr Arjun Ghosh, together with his co-author Dr Rebecca Dobson, have produced new guidelines on behalf of the British Society of Echocardiography and the British Cardio-Oncology Society, to guide cardiologists in the use of serial echocardiography, global longitudinal strain (GSL), and 3D echo.

So welcome to both of you. Susannah, if I can start with you: oncology is obviously a huge issue. Many thousands of patients are being affected with important malignancies, and we're grateful to see that there are so many advanced therapies available. But many of these can affect the heart and that can alter the way we give these therapies, and certainly alters the long-term prognosis for these patients. Can you expand on this area and tell me what some of the problems are?

Dr Susannah Stanway

Globally, more and more patients now are accessing cancer treatments. More patients are being diagnosed with cancer, incidence is rising, the patients we treat are getting older, and there are also many shared risk factors for cardiovascular disease, and also for cancer. So many of the patients we see will have pre-existing cardiovascular disease. And added to that, many of the drugs that we have in our anti-cancer armamentarium are cardiotoxic themselves in various ways.

I think that having collaborative work between cardiologists and the development of cardio-oncology services is incredibly important and will be becoming increasingly important.

So taking a cancer such as breast cancer, one person a minute is diagnosed at a global level with breast cancer. A country like the US will have around 3.5 million women who are either living with, or beyond, breast cancer and may have been exposed to potentially cardiotoxic drugs. And many of the patients who are diagnosed with breast cancer will receive drugs, such as anthracyclines, that can damage the heart, or monoclonal antibodies such as trastuzumab (Herceptin, Roche), which the guideline we're going to be talking about today refers to. As you said, yes, I think this is an incredibly important area of cardiology and oncology.

Dr Nijjer

You mentioned a number of different terms there. You talked about cardiotoxicity, and that's defined in various different ways. And you've also talked about a number of very specialist drugs that are used in the treatment of cancer patients, can you tell me which drugs and which chemotherapies in particular we have to be worried about in terms of cardiotoxicity?

Dr Stanway

Many of the drugs we use to treat cancer have a potential cardiotoxic readout. Obviously, when one's considering suitability of treatment, one has to look at what the data is behind its efficacy towards that cancer, and also on what the patient is like sitting in front of you.

So this definitely has to be a personalised, tailored approach, with adequate consent sought, and risks and benefits considered. And that's what we as oncologists do on a daily basis in clinic.

Speaking as a breast cancer specialist, I think probably trastuzumab, which is a monoclonal antibody, which we use for HER2+ breast cancer, which about a fifth of breast cancer is, and the anthracyclines are probably the drugs that we use where we worry the most about the heart. And I think that having that dialogue with cardiologists, knowing how to flag up patients that we are worried about, both before treatment in the primary setting, and in a preventative setting, and during treatment, is incredibly important.

Dr Nijjer

Arjun, you work very closely with oncologists and you've worked very hard in the cardio oncology space. Tell me, what do you understand by the term cardiotoxicity? And is there now an agreed definition?

Dr Arjun Ghosh

So that is really a very big question. That's something that a lot of guideline authors have been grappling with. And the situation prior to this guideline that we launched in the UK, was that every society had their own definition. The American Society of Echocardiography had a definition, the European Association of Cardiovascular Imaging had a definition, the Canadian Cardiovascular Society, and the list is endless.

What we have gone for is a bit more of a pragmatic definition aligned with what we do in the UK. Given that this is a British Society of Echocardiography guideline, we start with a normal ejection fraction being 50% or more, which is what the British Society of Echocardiography recommends.

Thereafter, a decline of more than 10 percentage points is something that we say is cardiotoxicity, which is in keeping with many of the other guidelines around the world. The difference is that we do go into probable subclinical cardiotoxicity and possible side subclinical cardiotoxicity, and we use GLS as an additional marker here. So GLS is a marker called global longitudinal strain. This is a more sensitive marker of cardiac function. This goes down earlier, before ejection fraction. So it gives us an idea that something detrimental may be happening to the heart, and is actually recommended in other guidelines, such as those from the ESC.

Dr Nijjer

OK, so you've talked about ejection fraction. Many clinicians working around the world will be familiar with that term, and this is basically an estimate of how good the left ventricular function is. And there are some limitations to ejection fraction. We know that the test-retest reproducibility of ejection fraction is relatively poor, and if you are serially monitoring patients on their ejection fraction, then natural fluctuation can happen. And so you have advocated the use of a newer parameter, global longitudinal strain. What's the availability of global longitudinal strain in a typical echo laboratory in the United Kingdom?

Dr Ghosh

Alongside the global longitudinal strain, I would just add that you talked about the reproducibility. So we also advocate the use of 3D echo, because that is more reproducible, and is somewhat closer towards MRI, which is the gold standard in terms of reproducibility. And if I take the availability of 3D echo and GLS together, actually, all new echo machines - and by new, I mean, for the last 8 years or so - do have these capabilities. So I would expect in the UK most departments would at least have one if not more machines younger than that. And they would have the built-in capability of doing GLS. So for GLS, you don't need a special echo probe it's with the normal 2D echo probe. For 3D, you do need a special probe, but as I said, it is pretty common practice. And it is recommended in the assessment of valve disease, and as a routine part of TOE (transoesophageal echocardiogram). So most echo departments in the UK would have one or more machines with this capability.

Dr Nijjer

It sounds to me that in the United Kingdom, this should be widely available, certainly in terms of the physical machines to be able to perform it. Without going too much into the detail of it, do you think that people are adequately trained and have enough experience to be able to be performing these kinds of measurements?

Dr Ghosh

Yeah, so again, it would probably boil down to the same as any new investigative technique or imaging technique, you do need, as you say, the experience to go ahead with this. And I would say that in most departments, normally there is at least one individual who has trained specifically in strain measurements, in global longitudinal strain and 3D. And that's often a physiologist, and it could be a cardiologist if they have a special imaging interest.

We hope, through our document, to actually spur the increase in training for physiologists and cardiologists in this modality, because we are cognisant of the fact that not every department has every individual trained in these modalities. So we recommend 3D and GLS as the gold standard, but we do also say that, if that's not available, Simpson's biplane would be the next best alternative. But as with any newer technique or emerging technique, we hope that once it's recommended in a national guideline, this actually spurs the uptake of training in this area.

Dr Nijjer

Yes, absolutely. So that's the key advantage, isn't it?, of coming up with a national guideline, that it really pushes people forward. Okay, so let's imagine a situation in which patients are all routinely being monitored using these technologies, and having their cancer care monitored, and having regular echocardiography.

Suzannah, how would you refer patients to cardiology or for echo for these tests? And how would you interpret the numbers that you get, and make treatment decisions for your patients?

Dr Stanway

I think that it's important at baseline to also consider risk-stratifying your patients. We published some iCOS (Imaging in Cardio-Oncology Study) and HFA (Heart Failure Association) of the European Society of Cardiology guidelines on that last year, and that will give you a good guide as to the kind of patient that might run into trouble, and also who you can reassure.

All patients should have baseline cardiac imaging, baseline investigations, baseline ECG, baseline blood pressure, and then depending on the treatment that they're receiving, interval imaging during treatment, and at the end of treatment. What's slightly more controversial is the surveillance post-treatment. I think that it's important to have regular dialogue with the cardiologists that you have your service level agreement with, such that if you're unsure as to how to interpret the values that you get, you can pick up the phone, drop an email, such that the patients get the best care that is possible.

Detailed in this guideline, as Arjun has just said, are exact numbers, and when one needs to be concerned with respect to drop in ejection fraction, and also change in GLS, and also symptomatology that one might be concerned about along the way.

I think that as an oncologist, those are the kind of things that one has to be aware of.

Dr Nijjer

Hopefully we've given the viewers a good overview of patients who have, particularly breast malignancies that need treatment with chemotherapy, particularly with the new agents, including those slightly older agents like the anthracyclines, and medications like Herceptin, then we need these patients to be carefully monitored, and there are clear cardiac guidelines now. And we would ask our viewers to look out for the new publication, which I understand is in two journals simultaneously.

Dr Ghosh

It came out recently in JACC CardioOncology, and was simultaneously published in Echo Research and Practice.

Dr Nijjer

So we'd advocate for all our viewers to look out for those guidelines, and see if you can implement that in your local centre. Thank you for watching.

Dr Susannah Stanway, MBChB MSc FRCP MD, Consultant in Medical Oncology. Dr Stanway has no relevant disclosures.

Dr Arjun Ghosh, MBBS MSc PhD FHEA FACC FESC FRCP FICOS, Consultant Cardiologist, UCLH and Barts Heart Centre. Dr Ghosh has no relevant disclosures.

You can follow Dr Sukh Nijjer on Twitter.

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