Cancer survivors face elevated heart disease risk, study finds

A new study has found that about 35% of Americans with a cancer history had an elevated risk of cardiovascular disease in the next decade, compared with about 23% of those who didn't have cancer.

Based on a risk calculator that estimates a person's 10-year chances of developing heart disease or stroke, researchers from The Ohio State University found that the average estimated 10-year risk for a cancer survivor was about 8%, compared to 5% for those who didn't have a history of cancer.

The new study appears in the journal PLOS ONE.

"We know that obesity, cancer and cardiovascular disease share some common risk factors, and in addition to those shared risk factors, cancer patients also receive treatments including radiation and chemotherapy that can affect their cardiovascular health—we call that cardiotoxicity," said lead researcher Xiaochen Zhang, a Ph.D. candidate in Ohio State's College of Public Health.

But those risks may be underestimated or poorly understood, leading Zhang and fellow researchers to urge steps to boost recognition among health care providers and their patients.

"The good news is that we're getting really good at treating cancer and we have more survivors, but we need to start thinking more carefully about the non-cancer risks following a diagnosis, one of which is cardiovascular disease," said study senior author Ashley Felix, an associate professor of epidemiology at Ohio State.

"We don't want people to survive cancer only to die prematurely of heart disease or stroke, so we need to make sure that cancer patients, and their health care team, are aware of this increased risk."

The data used in the study comes from the National Health and Nutrition Examination Survey conducted by the Centers for Disease Control and Prevention. The nationally representative sample of people surveyed from 2007 to 2016 should provide a good picture of the elevated risk for cancer survivors in the U.S., the researchers said.

For this analysis, they examined data provided by 15,095 adults aged 40 to 79 years with no history of cardiovascular disease. Almost 13% reported a history of cancer.

One of the strengths of this research is the large study size, which allowed for analysis based on type of cancer and by age group. Survivors of testicular, prostate, bladder and kidney cancers had particularly high 10-year cardiovascular disease risk, as did those in their 60s.

When the researchers compared individual cardiovascular disease risk factors by cancer status, they found that older age, higher systolic blood pressure and a personal history of diabetes were more common in the cancer survivors.

Looking forward, it's important that researchers and health care providers keep their eyes on the growing number of cancer survivors, including younger adults, Felix said. Almost 17 million Americans live with a cancer diagnosis, a number that is expected to grow to 26 million by 2040.

"If we continue to see the increasing incidence of cancer among younger adults, we can expect to see a larger burden of cardiovascular disease among those individuals—our future studies need to go in that direction," she said.

Added Zhang, "The good news is that those younger individuals have a lot of time to make lifestyle changes that could move their cardiovascular risk in a positive direction.

"In addition to monitoring cancer survivors carefully for cardiovascular disease—and making them aware of the elevated risk—health care providers have the opportunity to guide patients toward interventions that can lower their risk," she said.

There's also potential for developing a risk-assessment tool that specifically takes cancer survivorship into account—which would allow for more precise assessments for that population, the researchers said.