A new study of almost 19,000 UK Biobank participants previously diagnosed with cancer showed that they had an elevated risk of cardiovascular disease (CVD). Blood and breast cancer survivors may be at greatest risk, researchers found.
The study, published in the journal Heart, suggested that cancer history was linked to increased risk of incident CVD and adverse cardiac remodelling, independent of shared vascular risk factors.
While a heightened risk of CVD among cancer survivors was already recognised – indeed late last year it was suggested that cancer history be included as a predictor in cardiovascular risk scores – most of the evidence to date had suggested that the highest risk of cardiovascular complications arose in the first year after diagnosis. Few studies had looked at potential longer-term risks, or included imaging to assess cardiovascular system damage that hadn't yet resulted in symptoms.
The researchers, led by Dr Zahra Raisi-Estabragh, cardiology speciality trainee at the William Harvey Research Institute, Queen Mary University of London, conducted a prospective 12-year follow up to assess the cardiovascular health of 18,714 UK Biobank participants with a diagnosis of a common cancer, including lung (313), breast (9531), prostate (3291), blood (2230), uterus (937), or bowel (2412), and compared them with the same number of control participants, matched for age and traditional vascular risk factors.
Pre-existing CVD was relatively common, present in 18% of the cancer cohort, and almost a third of cancer survivors developed a new cardiovascular issue during the monitoring period, including ischaemic heart disease, stroke, atrial flutter/fibrillation, heart failure, impaired electrical signalling, non-ischaemic cardiomyopathy, venous thromboembolism, and pericarditis.
Mortality rates during follow up were 8.5% in controls versus 19% for cancer survivors, for 1 in 12 of whom CVD was the primary cause of death. Among the 1354 participants with cardiovascular magnetic resonance scans, cancer history was also linked to adverse cardiac remodelling. "Cardiovascular imaging has a key role in detecting subclinical cardiotoxicity," the researchers said.
The pattern of CVD varied by cancer site, likely reflecting specific characteristics both of the cancer and its treatments, the researchers said. The highest rates occurred in those with lung (49.5%), haematological (48.5%), and prostate (41%) cancers. Haematological cancer was associated with increased risk of all incident CVDs considered, with hazard ratios (HR) of 1.92 to 3.56. Breast cancer was associated with increased HRs for selected CVDs of 1.34 to 2.03. New cases of ischaemic heart disease, atrial fibrillation, and heart failure were the most common types of cardiovascular disease across all cancers.
'Particular Vulnerability' After Breast and Haematological Cancer
The researchers commented that their findings showed "particular vulnerability of individuals with past breast and haematological cancer", with both increased risk of incident clinical disease and adverse cardiac remodelling. Patients with haematological cancers are exposed to chemotherapies known to be cardiotoxic, as well as mediastinal radiotherapy. Similarly, raised CVD risks among breast cancer survivors "likely reflect cardiotoxicity" linked to treatments.
"Past cancer confers an increased risk of cardiovascular events, independent of traditional vascular risk factors, and this risk may extend several years beyond the initial cancer diagnosis," they said.
They concluded that the findings "support consideration of cancer-specific exposures in cardiovascular risk stratification, and lower thresholds for treatment of modifiable risk factors in this patient group."
In an accompanying editorial, José Banchs, professor of medicine- cardiology at the University of Colorado School of Medicine, and Dr Tara Lech PharmD, thrombosis program manager at Beth Israel Lahey Health in Burlington, said that the intersection between cardiology and oncology continued to expand. "The fantastic progress in the treatment and even cure of malignancies has undoubtedly highlighted the need for post cancer care like never before."
Asked to comment by Medscape News UK, Martin Ledwick, head information nurse at Cancer Research UK, said: "This study adds to existing knowledge about the impact of some cancer treatments on cardiovascular disease in cancer survivors. 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."
Anthony Cunliffe, lead medical adviser at Macmillan Cancer Support, told Medscape News UK: "It’s critical that people don’t just survive a cancer diagnosis but that they can live well, with the best possible quality of life.
"This research demonstrates the huge importance of healthcare professionals arming patients with the information they need about potential long-term effects of their treatment, and the signs and symptoms they should be looking out for.
"Empowering people to seek support from their clinical team if they have any concerns following cancer treatment also forms a vital piece of this puzzle, encouraging people to access help when needed and to live well after cancer."
No funding for the study was declared.