People who survive cancer may be at heightened risk of cardiovascular disease in subsequent years, data suggests.
However, heart scans may identify early heart damage, potentially opening the door to more tailored follow-up care for cancer survivors.
Although previous studies have suggested that people who have been treated for cancer may be at greater risk of future cardiovascular problems such as stroke or heart failure, these have mainly focused on the first year after a cancer diagnosis.
Few have looked at longer term risks or included cardiovascular imaging to pinpoint damage that has not yet resulted in symptoms.
To plug these gaps, Dr Zahra Raisi-Estabragh at 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 cancer history, tracking their cardiovascular health for nearly 12 years.
Almost a third of cancer survivors developed a cardiovascular problem during the study period, compared with a quarter of people in the control group.
The highest rates of new cardiovascular disease occurred in individuals who had survived lung or blood cancer, with almost half of them developing a cardiovascular problem in subsequent years – the most common being ischaemic heart disease, an abnormal heart rhythm and heart failure.
By contrast, the most common cardiovascular problems among breast cancer survivors were heart failure, inflammation of the lining around the heart (pericarditis) and mechanical heart problems.
These differences were most likely to be a reflection of specific characteristics of the cancer and its therapies, Raisi-Estabragh said.
The team also examined cardiac MRI scan results for the 1,354 study participants for whom these were available. Doing so revealed significant and detrimental changes in the size and function of the heart in breast and blood cancers survivors. The findings are published in the journal Heart.
Although this was an observational study, and cannot prove that the cancer, or cancer treatments, were the cause of this increased cardiovascular risk, patients with blood cancers were exposed to chemotherapies known to be harmful to heart tissue, as well as radiotherapy that targeted the chest wall, the researchers explained.
Some breast cancer therapies were also known to affect heart function, although it was likely that shared vascular risk factors, such as smoking, being overweight or having diabetes – as well as biological processes related to the cancer itself – also contributed to this increased cardiovascular risk among cancer survivors.
“This study adds to existing knowledge about the impact of some cancer treatments on cardiovascular disease in cancer survivors,” said Martin Ledwick, the head information nurse at Cancer Research UK.
“It may help to inform strategies for how some cancer survivors need to be monitored long-term, especially in situations where they have been discharged from cancer follow-up to the care of their GPs.”
Writing in a linked editorial, Prof Jose Banchs of the University of Colorado and Dr Tara Lech from Beth Israel Lahey Health in Massachusetts, said: “The fantastic progress in the treatment and even cure of malignancies has undoubtedly highlighted the need for post-cancer care like never before.”
Confirmation that enhanced cardiovascular risk extended for a prolonged time after a cancer diagnosis – and that certain detrimental changes could potentially be identified on heart scans before patients developed symptoms – should enable doctors to start refining follow-up strategies for such individuals.