The research, to be presented at the American College of Cardiology’s Annual Scientific Session in Chicago, analyzed data from more than 630,000 patients.
“To our knowledge, this is the first population-based study assessing disparity in cardiovascular mortality in different groups among patients diagnosed with colorectal cancer,” says study author Ahsan Ayaz, MD, an internal medicine resident at Montefiore St. Luke’s Cornwall Hospital in Newburgh, New York.
Looking at such a large dataset allowed the researchers to find out which subgroups faced the highest risks, and how to mitigate those risks for the best survival outcomes, Dr. Ayaz says.
The First 2 Years After Diagnosis Are Critical
Ayaz and his team looked at medical information on people diagnosed with colorectal cancer between 2000 and 2021.
They included in their analysis anyone who died from complications of:
- Heart disease
- High blood pressure
- Cerebrovascular diseases such as stroke
- Atherosclerosis, or blocked arteries
- Aortic aneurysm, a bulge in the main artery of the body
The research found that the chances of dying from heart problems were highest in the first two years after a colorectal cancer diagnosis. During this period, the risk was 45 percent greater.
While the study doesn’t directly address the reasons, this period coincides with intensive cancer treatment, including chemotherapy, radiation, and surgery — each of which can impact cardiovascular health, says Robert S. Copeland-Halperin, MD, an assistant professor of cardiology at the Zucker School of Medicine at Northwell Health in Uniondale, New York, and a member of the cardio-oncology council of the American College of Cardiology.
“Previous studies have also shown an initial spike in risk within the first year, with another increase beyond five years, likely reflecting long-term effects of treatment and survivorship-related factors,” says Dr. Copeland-Halperin, who was not involved in the research.
Identifying Groups at Highest Risk of Dying
For adults younger than 50, the odds of dying were especially pronounced. This population was 2.4 times more likely to die of heart-related causes than people in the same age group who did not have colorectal cancer.
At this point, researchers don’t know why this is the case. Ayaz calls it one of the “most curious” questions yet to be answered, although he does point out that the incidence of colorectal cancer has been increasing in younger adults.
It could be that this younger population faces a higher risk of death because early onset colorectal cancer is more aggressive, requiring more intensive treatment that impacts the heart, says Salim Hayek, MD, a cardiologist with the University of Texas Medical Branch at Galveston and the chair of the American Heart Association’s cardio-oncology committee.
“Possible genetic factors may also link early-onset colorectal cancer with cardiovascular vulnerability,” says Dr. Hayek, who was not involved in this research.
He adds that cancer treatments, particularly chemotherapies like 5-fluorouracil commonly used in colorectal cancer, can damage the cardiovascular system. These treatments may cause:
- Vasospasm (when arteries constrict)
- Ischemia (reduced blood flow to the heart)
- Arrhythmias (irregular heartbeats)
- Indirect effects such as new high blood pressure accelerated plaque buildup in the arteries
The study found that Black adults with colorectal cancer faced a 74 percent higher risk of death from heart complications.
How to Lower Your Risk of Heart Problems After Colorectal Cancer Diagnosis
Because this two-year period is critical, Ayaz advises his patients to make a concerted effort to control heart disease risk factors during this time.
“Ask questions of your treating doctors about your personal risk factors for developing heart disease, especially when facing a cancer diagnosis, and ask about cardiovascular risks associated with the proposed treatment for your cancer,” says Helga Van Herle, MD, a cardiologist with Keck Medicine of USC in Pasadena, California, who was not involved in the study.
To reduce cardiovascular risk factors, she recommends:
- Treating high cholesterol
- Managing high blood pressure
- Treating diabetes
- Quitting smoking
- Losing weight if necessary
- Following a healthy diet
- Getting exercise
“While patients diagnosed with cancer can’t change the past, we know that potentially treatable risk factors including lifestyle and conditions like high blood pressure, diabetes, and elevated cholesterol increase the risk for heart related complications,” says Copeland-Halperin. “So addressing these represents a significant potential opportunity to improve the outcomes.”