More childhood cancer survivors are experiencing cardiomyopathy and other cardiotoxicities years after treatment with anthracyclines than previously thought, say researchers who have reported the first outcomes from an Australian cohort of paediatric cancer survivors.
Cardiologists and oncologists are now calling on national bodies to fund a paediatric cancer survivor register and are urging doctors to be aware of the lifelong risk of anthracycline cardiotoxicity in patients who have survived their cancer.
“The reality is that when paediatric cancer survivors present with a life threatening cardiac complication they are often still young, usually under the age of 30, they’ve never seen a cardiologist and their first presentation is near death … that’s the sad thing about it,” said paediatric oncologist at Melbourne’s Royal Children’s hospital, Dr Rachel Conyers who was the lead author on the paper published in Internal Medicine.
She said a registry of cancer patients exposed to any cardio-toxic drug would help to centralise critical patient information down the track.
“The idea would be that any clinician would be able to contact the registry to get an update on what cardiac data is available for their patient,” she told the limbic.
She said while more paediatric cancer patients are surviving their cancer, a darker side to that outcome is that many more will present with serious cardiac complications.
Dr Conyers noted that 1 in 5 cancer survivors in their study experienced anthracycline cardiotoxicity – a figure that was much higher than the historically reported two percent.
According to Dr Conyers the figure is also likely to be conservative given a quarter of the original cohort (26% of 481 patients) exposed to anthracycline were excluded from the study because they hadn’t had a baseline echocardiogram or had inadequate imaging.
“The number of patients that have been exposed to anthracyclines is far greater than it used to be based on the number of patients surviving their cancer,” she said.
A rationale for screening
More than half of the patients participating in the study developed cardiotoxicity within six months of exposure with the other half arising over the course of six years.
However the time to cardiotoxicity onset did not appear to correlate with disease severity, Dr Conyers said.
For the majority of patients who develop anthracycline cardiotoxicity the cardiac damage is irreversible and a large proportion of patients have no symptoms to indicate they have a cardiac problem.
Dr Conyers said screening LVEF function with imagery every 1-5 years is currently recommended by the US Children’s Oncology Group – a recommendation which is followed at the Royal Children’s Hospital.
And newly published European guidelines recommend screening within two years of the last anthracycline exposure and then, at a minimum, life-long screening every five years.
“The rationale for screening is that early heart failure therapies like ACE inhibitors and beta-blockers may delay the onset of congestive heart failure,” Dr Conyers said.
The study is part of a larger project, which will see researchers analyse blood samples taken from the entire cohort of patients plus an 1,200 samples taken from patients nationally to find out if there is a genetic link that might help identify which patients will go on to develop anthracyline cardiotoxicity.
“The idea would be that you may be able to very quickly identify at diagnosis which patients are at risk of developing cardiotoxicity, which will give the clinician the ability to make decisions around whether they use the drug or whether they use a protective drug at the same time.
“It might also mean that new protective agents are discovered as well,” Dr Conyers said.