A history of cancer should be considered a risk factor for cardiovascular disease and be included in risk calculators, UK clinicians say.
The recommendation follows a study showing that cancer survivors have more than a 50% increased risk of conditions such as heart failure and cardiomyopathy compared to the general population.
The retrospective study published in The Lancet which compared risks between 126,000 adult survivors of 20 cancers and 630,000 matched controls with no history of cancer found that people with solid cancers had increased risks across a wide range of cardiovascular outcomes.
The risks of heart failure or cardiomyopathy were particularly raised in patients with a history of oesophageal (Hazard Ratio 1·96), lung (HR 1.82), kidney (HR 1.73), and ovarian (HR 1·59) cancers, the researchers from the London School of Hygiene and Tropical Medicine reported.
Increased medium to long term increased risks of arrhythmia, pericarditis, coronary artery disease, stroke, and valvular heart disease were also seen for multiple cancer sites.
One “striking” finding was that the risk of venous thromboembolism was elevated in patients for at least 5 years after diagnosis compared with that of controls with no history of cancer, even among patients with no record of receiving chemotherapy, the researchers noted.
They suggested this could be explained by the long-term effects of the underlying malignancy, long-term endocrine therapies, or residual confounding by shared risk factors.
The causes of increased cardiovascular risk were likely to be varied, but cancer treatments, particularly chemotherapy, were likely to play a more prominent role than shared risk factors such as smoking and excess weight, the researchers concluded.
Nevertheless, they suggested that it might be time to include cancer history in cardiovascular risk calculators, particularly as prediction models used in general practice typically did not include outcomes such as heart failure and venous thromboembolism or cancer.
“These models generally ignore competing risks, which are likely to be important in a cancer survival setting,” they wrote.
“Clearly, more and better education and awareness is needed among GPs, other clinicians, and patients, so that preventive strategies can be considered and implemented…Available information for clinicians is insufficient, and the development of comprehensive, evidence-based, national-level guidance on cardiovascular considerations in cancer survival care could be prioritised to help optimise the care of this patient group,” they concluded.
Writing in an accompanying editorial, clinicians from the University of Minnesota said the study adds to the ‘strong case’ for research as to whether the inclusion of cancer history in risk prediction tools would add incremental value in the general population.
“In the meantime, clinicians should account for cancer, and especially chemotherapy, as a risk factor for cardiovascular disease when discerning individual patient risks to guide preventive interventions,” they advised.
Speaking to the limbic about the study, Professor Simon Rule, a professor of haematology at Plymouth University Medical School in the UK stressed that the relative risks seen in the study were still low.
“It does flag up there is an increased risk but its reassuring to see the risk is perhaps not as high as some had made it out to be,” he said.
“It is also important to remember that you don’t get these effects unless you survive. We need to be cautious that we don’t modify therapies and end up reducing the effectiveness of treatment.”
He said long-term follow up from oncology teams would be unrealistic.
“But including it in cardiovascular risk tools is a good idea,” he added.