A study by UK Biobank has found that cancer survivors may be at long-term heightened risk of cardiovascular disease, irrespective of traditional underlying risk factors, with those who have survived blood cancer and breast cancer, most vulnerable.
While most of the evidence to date suggests that the highest risk of cardiovascular complications arises in the first year after diagnosis, few studies have looked at potential longer term risks or included cardiovascular imaging to pinpoint cardiovascular system damage that hasn’t yet resulted in symptoms.
To plug these knowledge gaps, the researchers assessed, whose findings are pubished in the journal Heart, the cardiovascular health of 18,714 UK Biobank participants with a previous diagnosis of a common cancer—lung (313), breast (9531), prostate (3291), blood (2230), womb (937), or bowel (2412)—and compared them with the same number of UK Biobank participants without any history of cancer, and matched for age and traditional vascular risk factors. The average age of all the participants was 62, and around two-thirds were women and their cardiovascular health was tracked for nearly 12 years using linked health records.
Factors associated with worse cardiovascular health, including smoking, high blood pressure, and excess weight were common among those with a previous cancer diagnosis. Nearly 1 in 10 of those with lung, womb, and bowel cancers had diabetes. Pre-existing cardiovascular disease was also relatively common found in 18% of those studied.
The team’s findings showed that almost one-third of cancer survivors developed one of the following during the monitoring period: ischemic heart disease; stroke; abnormal heart rhythm (atrial fibrillation); heart failure; impaired electrical signaling or mechanical heart problems (non-ischemic cardiomyopathies); blood clots in the veins, arteries, or lungs; inflammation of the lining around the heart (pericarditis).
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 ischemic heart disease, atrial fibrillation, and heart failure the most common types of cardiovascular disease across all cancers.
During the monitoring period, 19% of the 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. MRI scan results for 1,354 of the study participants also showed that the size and function of the heart among the cancer survivors had substantially altered for the worse, irrespective of underlying vascular risk factors.
Blood cancer survivors had significantly increased risks of developing all the cardiovascular disease types considered compared with their peers without cancer. Clinically significant changes in the size and function of their hearts were also evident on MRI scans. Patients with blood cancers are exposed to chemotherapies known to be harmful to heart tissue, as well as radiotherapy that targets the chest wall overlying the heart, explained the researchers.
Breast cancer survivors also exhibited 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.
“These observations likely reflect cardiotoxicity linked to breast cancer therapies,” noted out the researchers, adding that these people were also eigt times more likely to die of disease associated with high blood pressure.
The researchers cautioned that their work was an observational study and can’t establish the cause of the increased risk. There were also various limitations acknowledged by the team, including the small numbers of lung and womb cancer survivors and no information on cancer grade, stage, or specific treatments. Most of the UK Biobank study participants are also White, so the findings might not apply to people of other ethnic backgrounds.
Nevertheless, they concluded: “Importantly, we demonstrate that past cancer confers an increased risk of cardiovascular events, independent of traditional vascular risk factors and that this risk may extend several years beyond the initial cancer diagnosis.”
Their findings show “particular vulnerability of individuals with past breast and hematological cancer, who appeared at greatest risk, both with regards to risk of incident clinical disease and adverse cardiac remodeling,” the researchers noted.
