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Previous research has linked cancer drugs known as anthracyclines to
weakening of the heart muscle. Research has also tied some radiation
therapy to cardiac rhythm disorders and structural damage in
arteries and valves.
The current study not only reinforces these risks, it also suggests
that many childhood cancer survivors may encounter serious cardiac
issues at a relatively young age when doctors may not routinely
screen patients for heart disease, said lead study author Dr. Daniel
Mulrooney of St. Jude Children’s Research Hospital.
“A heart-healthy lifestyle, important for all patients, has
increased importance for childhood cancer survivors who are at risk
for cardiac disease at an earlier age than their peers,” Mulrooney
said by email.
To assess the prevalence of cardiac problems among former cancer
patients, Mulrooney and colleagues examined data on 1,853 adult
survivors of childhood tumors who received treatments associated
with heart damage.
About half of the survivors were men. Overall, half the patients had
been less than eight years old when they were diagnosed.
At the time of their cardiac evaluations, half were at least 31
years old.
More than 82 percent of participants had received anthracyclines
during their cancer treatment, and more than 20 percent took higher
cumulative doses of this chemotherapy that are linked to even
greater odds of heart damage.
Fewer than half of the survivors received radiation to the heart,
but about 22 percent had a higher cardiac dose linked to an
increased risk of complications down the line.
The prevalence of cardiac conditions increased with age at
evaluation, ranging from 3 to 24 percent among survivors aged 30 to
39, to 10 to 37 percent among those 40 and older, the researchers
report in the Annals of Internal Medicine.
Overall, 7.4 percent of the survivors had cardiomyopathy, or chronic
disease of the heart muscle, and 3.8 percent had coronary artery
disease, the study found.
In addition, 28 percent had leaking or narrowing of heart valves and
4.4 percent had heart rhythm abnormalities.
Very few survivors had symptoms, and many of them weren’t diagnosed
with heart problems until they received evaluations as part of the
study.
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One limitation of the study is that it only included cancer
survivors, making it impossible to compare the risk of heart damage
to people who didn’t have cancer, the authors note.
Newer treatment protocols established since these patients were
treated more than a decade ago have also reduced exposure to
chemotherapy and radiation that can damage the heart, Mulrooney
said.
Some preliminary research has also suggested that a family of
medicines known as beta-blockers might be given to childhood cancer
patients to potentially minimize the future risk of heart damage,
said Dr. Jean-Bernard Durand, medical director of the cardiomyopathy
service at the University of Texas MD Anderson Cancer Center in
Houston.
Except in rare instances, however, parents would not want to avoid
treating cancer to minimize future heart risks, Durand noted. An
exception might be made for kids whose heart function was so weak
that receiving chemotherapy might overwhelm the heart.
Instead, patients who survive cancer should focus on making sure
they have a complete record of the timing and dosage of any tumor
treatments they received and alert doctors that they require cardiac
screenings, Durand said. If they have other risks for heart disease,
such as a family history, diabetes or high blood pressure, they need
to be all the more vigilant, he added.
“Nearly all of the survivors in this study were asymptomatic in
their 30s and 40s when they walked into the doctor’s office, and
results show that they needed the physical normally given to
patients in their 50s and 60s that includes a complete cardiac
evaluation,” Durand added by email.
SOURCE: http://bit.ly/1i46lF7 Annals of Internal Medicine, online
January 4, 2016.
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