Chemotherapy gave me an irregular pulse and a stroke!
ATRIAL Fibrillation (AF) is a heart rhythm disturbance that increases the risk of stroke fivefold for those diagnosed with the condition.
There are no symptoms of AF, so for many people a diagnosis comes as a result of a routine health check where an irregular pulse is detected. In other cases, AF is picked up after a serious health incident, such as a stroke.
In Nicola Neame’s case, the first signs of AF appeared just weeks after she had finished a course of chemotherapy for cancer.
As she digested the news that her breast cancer had not only come back, but had spread to her bones, 55-year-old Nicola’s ‘overriding concern’ was to get the disease under control.
‘I knew that secondary breast cancer is not curable, but it is treatable,’ she says.
Nicola embarked on a 20-week course of chemotherapy to stabilise the cancer, but while it stopped the disease progressing, it had a side-effect that she wasn’t expecting: it damaged her heart.
She began to experience palpitations. ‘It felt as if my heart was skipping a beat at times,’ says Nicola, who is married to Mike, 55, and has two grown-up daughters. ‘It happened only occasionally and I wasn’t overly worried.’
Nonetheless, Nicola was referred to a cardiologist who diagnosed AF — a condition that causes an irregular and often abnormally fast heart rate. She was given medication that seemed to help.
But five years later, in April 2013, her health took a turn for the worse. A routine scan revealed her cancer had spread to her liver — which, she says, ‘came as a huge shock, after years of stability’.
There was yet another blow: Nicola’s heart suddenly deteriorated. Her heart rhythm problem became constant, and her heart was functioning well below normal: she had heart failure.
Not only was this hugely disruptive to her life, leaving her constantly breathless and uncomfortable but it meant she would not be able to take Herceptin, a cancer drug that could help keep her alive — her doctors said it would put too much strain on her heart.
‘That was when I started to feel really low,’ says Nicola. ‘It was the first time I felt that I wasn’t on the right treatment for my cancer.’
Herceptin (or trastuzumab) works by attacking cancer cells that produce high levels of a protein called HER2, and is sometimes used to slow the growth of advanced cancers that have spread beyond the breast.
But it can also damage the pumping action of the heart, with the risk higher in patients with a pre-existing heart problem.
This is because a heart that is under strain — for example due to high blood pressure or certain chemotherapy drugs — also produces the HER2 protein, this time as a protective mechanism.
‘In cancer, this protein is the bad guy, but in the heart muscle it’s the good guy, and if you block it with Herceptin that can make the heart problem worse,’ says Dr Alex Lyon, a consultant cardiologist. ‘In up to 15 per cent of women who take Herceptin, it causes heart failure or heart dysfunction.’
Herceptin is the ‘poster child’ of an increasingly common problem, says Dr Lyon. It’s one of a number of cancer treatments that can damage the heart. ‘The treatments that cause problems can be broadly divided into some of the traditional chemotherapy drugs, and many of the so-called designer drugs, which are targeted molecular therapies,’ says Dr Lyon.
‘They work in different ways, but essentially they block a molecule or pathway in a cancer cell. However if that molecule has an important role in heart function, then blocking it can be trouble.’
Radiotherapy, too, can affect the heart, for example when used to treat left-sided breast cancer — the radiation can cause inflammation which can raise the risk of coronary heart disease.
And some hormone therapies for prostate cancer — which help prevent testosterone fuelling the cancer — increase levels of ‘bad’ cholesterol in the body, which can raise the risk of heart disease.
The irony is that this situation is a by-product of the success of modern medicine. There are now more than 150,000 people living with and beyond cancer in Ireland, which means many are living long enough for the long-term sideeffects of their treatment to show.
‘Thirty years ago, half of those diagnosed with cancer lived only for a year, but now 50 per cent of those diagnosed live for ten years or more,’ says Dr Lyon.
‘A growing number have heart problems, which seems directly related to the treatments.
IT’S not that these cancer therapies are bad and should be stopped; they are working and we need to support them so that they can be given safely.
‘A lot of this cardiotoxicity is preventable — for example, by controlling risk factors for heart disease, or by monitoring the heart and giving medication at the early signs of heart failure.’
Although Nicola was vaguely aware that her heart problems were most likely triggered by her cancer treatment, it wasn’t until she had a mini-stroke in June 2013 that the hospital stopped treating the issues separately.
‘One morning I tried to speak and found my words did not come out properly,’ she says.
Tests showed she had heart failure as a result of her chemotherapy; the heart failure had triggered her heart rhythm problem.
She was given medication to strengthen her heart. She also had a cardioversion (where an electrical current restores an abnormal heart rhythm) followed by an ablation, where wires deliver high-frequency radiowaves to destroy the diseased area of the heart.
Crucially, the combination meant that in 2014 Nicola’s heart recovered enough for her to start Herceptin and another cancer drug, Perjeta. Although Nicola’s cancer remained stable for a further two years, in the past year it has progressed, so she has been switched to a different drug.
She is still having regular heart check-ups and has had no further major problems with her heart.
‘Having secondary breast cancer is so difficult anyway,’ she says. ‘What you don’t need is the extra problems of severe heart failure. It can cause so much anxiety, particularly if it has stopped you getting the cancer treatment you really need.’