UK Biobank study suggests a greater risk for blood and breast cancer survivors.
Model of a human heart. Photo by Robina Weermeijer
Cancer survivors may be at long term heightened risk of subsequent cardiovascular disease, irrespective of traditional underlying risk factors, according to the results of a large UK Biobank study, published online in the journal Heart.
The study shows that shared vascular risk factors as well as the treatments and biological processes related to the cancer itself are all associated with a heightened risk of incident cardiovascular disease among cancer survivors.
Previous studies suggest that the highest risk of cardiovascular complications arises in the first year after cancer diagnosis. Few studies have looked at longer term risks or included cardiovascular imaging to pinpoint damage that has not yet resulted in symptoms.
Dr Zahra Raisi-Estabragh from Queen Mary University of London and her colleagues assessed the cardiovascular health of 18,714 UK Biobank participants with a previous diagnosis of lung, breast, prostate, blood, womb, or bowel cancer, and compared them with an equal number of participants with no history of cancer, matched on age and traditional vascular risk factors. Their cardiovascular health was tracked, using linked health records, for nearly 12 years.
Almost a third of cancer survivors developed one of the following during the monitoring period: ischaemic heart disease; stroke; abnormal heart rhythm (atrial fibrillation); heart failure; impaired electrical signalling or mechanical heart problems (non-ischaemic cardiomyopathies); blood clots in the veins, arteries, or lungs; inflammation of the lining around the heart (pericarditis). The risk of developing the same cardiovascular conditions was lower in the comparator group at 25%.
The highest rates of new cardiovascular disease occurred in those with lung (49.5%), blood (48.5%), and prostate (41%) cancers, with new cases of ischaemic heart disease, atrial fibrillation, and heart failure the most common types of cardiovascular disease across all cancers.
During the monitoring period, 19% of cancer survivors died compared with 8.5% of those in the comparison group. Cardiovascular disease was the primary cause of death in 1 in 12 of the cancer survivors who died.
Researchers examined MRI scan results for the 1,354 study participants. Their findings revealed that the size and function of the heart among breast and blood cancer survivors had substantially altered for the worse, irrespective of underlying risk factors.
Patients with blood cancers are often exposed to chemotherapies known to be harmful to heart tissue, as well as radiotherapy targeting the chest wall overlying the heart, the researchers explained.
Similarly, breast cancer survivors had a heightened risk of developing, and dying from, heart failure and non-ischaemic cardiomyopathies, as well as being diagnosed with pericarditis. Their scans were also more likely to show evidence of functional heart changes.
In a linked editorial, Prof Jose Banchs and Dr Tara Lech of the University of Colorado School of Medicine, USA, said: “The importance of heart disease in patients undergoing cancer care cannot be understated, but also how critical it becomes to prioritise a care continuum after cancer is survived.
"The fantastic progress in the treatment and even cure of malignancies has undoubtedly highlighted the need for post cancer care like never before."
This is an observational study, and cannot establish cause. The researchers also acknowledge various limitations to their findings, including small numbers of lung and womb cancer survivors, no information on cancer grade, stage or specific treatments, and a lack of ethnic diversity among the study participants.