Colon cancer is a particularly deadly form of the disease, the second most common cause of cancer deaths in the U.S.

But patients diagnosed with colon cancer also need to be concerned about their heart health, especially if they're younger adults, a new study says.

Colon cancer patients under 50 are 2.4 times more likely to die from heart disease within the first two years of their cancer diagnosis, according to findings scheduled for presentation Sunday in Chicago at a meeting of the American College of Cardiology.

All patients with colon cancer also face an increased risk of heart-related death, and that risk runs highest within two years of their diagnosis, results show.

But younger adults, Black patients, and men are at especially high risk, researchers found.

"Based on our findings, the two-year period after a colorectal cancer diagnosis is a critical period when patients need aggressive care to improve cardiovascular outcomes," said researcher Dr. Ahsan Ayaz, an internal medicine resident at Montefiore St. Luke's Cornwall Hospital in Newburgh, N.Y.

"For example, there should be an aggressive approach to control cardiovascular risk factors and comorbidities like diabetes and hypertension," Ayaz said in a news release. "There is also a need for coordination between oncology teams and primary care teams, because most of those risk factors are managed by primary care providers."

The findings are troubling given that colon cancer rates are rising among people younger than 50, even as they decline among seniors.

Colon cancer rates rose by 2.4% a year among people under 50 between 2012 and 2021, according to the American Cancer Society.

Likewise, death rates in people under 55 have been increasing about 1% a year since the mid-2000s, the ACS said.

Previous studies have shown that cancer survivors have an increased risk of heart disease, but the relationship between cancer and heart-related death has not been well-studied, researchers said in background notes.

For the new study, researchers analyzed National Cancer Institute data on more than 630,000 adults diagnosed with colon cancer between 2000 and 2021.

Researchers looked for colon cancer patients who'd died from heart diseases, high blood pressure, stroke, hardening of the arteries, or a tear or clot in the aorta — the largest artery in the human body.

Overall, people with colon cancer were 16% more likely to die of heart problems than people without colon cancer, researchers found.

But in the first two years after diagnosis, the risk was 45% higher for all colon cancer patients, 55% higher for men, and 74% higher for Black patients, results show.

This increased risk of heart-related death could stem from side effects of cancer treatment, Ayaz said. For example, chemotherapy and radiation therapy are both known to be toxic to heart health.

The cancer itself also might cause inflammation and other problems damaging to the heart, he added.

"For therapies that are newer, there is not a lot of data on the side effects and toxicities, but evidence is emerging that they cause cardiovascular toxicity," Ayaz said. "It is important to identify these problems promptly and take steps to mitigate them."

Researchers next plan to review heart-related deaths among patients receiving different cancer treatments, and to see whether other factors like wealth, insurance or health care access influences their heart risk.

Findings presented at medical meetings should be considered preliminary until published in a peer-reviewed journal.