Patients who have suffered from heart failure may also face an increased risk of developing cancer.
The research, presented at Heart Failure 2021, an online scientific congress of the European Society of Cardiology, and published in the journal ESC Heart Failure, reviewed 200,000 Europeans and found that those with heart failure are more likely to develop cancer.
However, scientists say the evidence does not prove heart failure causes cancer - but that there's a correlation that means interventions should be targeted at heart patients, and other research that suggests a link.
"This was an observational study and the results do not prove that heart failure causes cancer," said study author Dr. Mark Luedde of the Christian-Albrechts-University of Kiel and Cardiology Joint Practice Bremerhaven, Germany. "However, the findings do suggest that heart failure patients may benefit from cancer prevention measures."
A total of 100,124 patients with heart failure and 100,124 individuals without heart failure were included in the analysis, and were matched by sex, age, obesity, diabetes, and consultation frequency.
No participants had cancer at the start of the study, and statistical models were used to examine the association between heart failure and the incidence of cancer over a decade. During the 10 year observation period, the incidence of cancer was 25.7 per cent - much higher than the 16.2 per cent incidence in those without.
The greatest increase in risk was observed for cancer of the lip, oral cavity, and pharynx, followed by respiratory organ cancer.
Dr. Luedde added: "Our results allow us to speculate that there may be a causal relationship between heart failure and an increased rate of cancer. This is biologically plausible, as there is experimental evidence that factors secreted by the failing heart may stimulate tumour growth.
"While heart failure and cancer share common risk factors such as obesity and diabetes, these were accounted for in the analysis by matching. It should be noted that our database does not include information on smoking, alcohol consumption or physical activity, so we were unable to match for these in the analysis."
Luedde suggested that just as cancer patients are monitored for heart failure, those who suffer from heart problems should also be observed for early signs of cancer.