Adults newly diagnosed with cardiovascular disease had a 65% higher risk of developing cancer in the year that followed, compared with people without a heart diagnosis.
That is the headline finding of a large study in the International Journal of Cancer, which tracked 568,926 European adults for a median of 10.9 years.
The work was led by Emma Fontvieille at the International Agency for Research on Cancer in Lyon.
It drew on two of the largest health cohorts on the continent, the European Prospective Investigation into Cancer and Nutrition and the UK Biobank.
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All participants were free of heart disease, cancer, and type 2 diabetes when they enrolled.
Where the risk spikes
The increase was concentrated in year one after the heart diagnosis, with a hazard ratio of 1.65. Between one and five years, the overall risk returned close to baseline. After five years, it was flat.
The pattern differed by sex. In women, the elevated cancer risk lingered for up to five years after a heart diagnosis. In men, it faded once the first year was up.
Lung cancer was the standout driver, with almost triple the risk in the first year after a new heart diagnosis.
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Colorectal cancer risk was also raised. Breast cancer showed no significant association.
Why heart disease and cancer travel together
Heart disease and cancer share biological ground. A 2025 review in JACC: CardioOncology describes chronic inflammation as a critical link between the two, alongside oxidative stress, cellular aging, and metabolic dysregulation. Common risk factors, including aging, obesity, smoking, diabetes, and high blood pressure, push people toward both diseases.
The Fontvieille team also flagged another explanation. Patients with a new heart diagnosis are pulled into intensive medical monitoring, and that surveillance can uncover cancers that were already growing quietly.
The authors describe this as overdiagnosis, and note it is especially likely in men, whose spike was confined to year one and then vanished.
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The persistent elevation in women is harder to write off as detection bias.
It suggests a biological link that reaches beyond an initial workup. The authors point to obesity and smoking as shared drivers of both diseases.
What it means for patients
The full study text notes an important caveat. The researchers had no data on heart medications, some of which may influence cancer risk in their own right, so those results should be read with that gap in mind.
They did adjust for age, smoking, alcohol, physical activity, body-mass index, education, diet quality, and menopausal status.
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The concentration of cancers in the first year after a heart diagnosis points to a concrete conversation to have with a doctor.
Anyone recently diagnosed with heart disease should ask their cardiologist or primary-care doctor about age-appropriate cancer screening, particularly for lung and colorectal cancer.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.