David Baraghoshi, MSTAT candidate

COMPARED TO the general population, the risk of cardiovascular disease among colorectal cancer survivors was significantly increased more than 10 years after their cancer diagnosis, according to research presented by David Baraghoshi, MSTAT candidate, of the Huntsman Cancer Institute at the University of Utah, Salt Lake City, and colleagues, at the 2018 Cancer Survivorship Symposium in Orlando.¹ 

“We believe this increased risk for cardiovascular disease among colorectal cancer survivors may be due to the shared lifestyle risk factors between the two diseases,” said Mr. Baraghoshi. Specifically, there was an increased risk of cardiovascular disease for survivors who were aged 65 years or older, had 1 or more comorbidities, and were obese. 

Study Background 

APPROXIMATELY 1.5 MILLION colorectal cancer survivors are currently living in the United States, and the 5-year survival rate has increased from 50% for patients diagnosed in the 1970s to around 66% for patients diagnosed more recently. 

“With more cancer patients surviving for longer periods, it’s important to determine whether colorectal cancer survivors experience a higher risk of certain diseases following their cancer treatment,” said Mr. Baraghoshi. “One such disease that may pose a higher risk for colorectal cancer survivors is cardiovascular disease, but few studies have examined the relationship between colorectal cancer survivorship and long-term cardiovascular disease risk.” 

The investigators conducted a population-based cohort study in order to estimate the risk of cardiovascular disease more than 10 years after diagnosis among colorectal cancer survivors. 

Individuals diagnosed with colorectal cancer between 1997 and 2013 were identified using the Utah Population Database. For a comparison group, up to five cancer-free individuals were matched by birth year, birth state, follow-up time, and sex to each cancer case. Data on cardiovascular disease diagnoses came from two large health-care providers in Utah and from statewide data on ambulatory surgeries and inpatient data. 

The team identified 1,749 colorectal cancer survivors and 6,480 individuals from the general population with at least 10 years of follow-up. Of the cancer survivors in the study, 1,001 (57.2%) were diagnosed with cardiovascular disease more than 10 years after their cancer diagnosis. 

In both the survivor population and the general population, there were slightly more males than females. A significantly higher mortality rate was observed among the colorectal cancer survivors compared to the general population, and survivors had a mostly localized disease stage, with a mean age at diagnosis of around 60 years. Overall, 72 cardiovascular disease outcomes were examined. 

Key Findings 

FOR BOTH the cancer survivors and the general population, the two most common diagnoses were hypertension and diseases of the heart. “For these more broadly defined cardiovascular diseases, we found the risk of diagnosis was twofold higher among the cancer survivors compared with the general population,” Mr. Baraghoshi reported. They also found a significantly increased long-term risk of diagnosis for more specific disease definitions such as acute myocardial infarction and transient cerebral ischemia. 

In addition, the team identified certain demographic factors associated with an increase in the long-term risk of cardiovascular disease among the survivors: male sex, older age at diagnosis, obesity at baseline, family history of heart disease, smoking at baseline, and hypertension at baseline. However, race and rural vs urban residence at diagnosis were not significant factors in determining the risk of cardiovascular disease among survivors. 

Colorectal cancer survivors with one or more comorbidities at baseline had almost double the risk of cardiovascular disease more than 10 years after their diagnosis, compared with survivors with no comorbidities. “Interestingly, however, clinical factors such as cancer site, cancer treatment, and cancer stage were not significant in assessing the risk of cardiovascular disease more than 10 years after the cancer diagnosis,” he noted. 

The researchers suggested further research to investigate the relationship between colorectal cancer and cardiovascular disease risk, specifically with respect to physical activity and how it can potentially mitigate the risk of cardiovascular disease in the long term after a cancer diagnosis. 

DISCLOSURE: Mr. Baraghoshi reported no conflicts of interest. 

REFERENCE 

1. Baraghoshi D, Hawkins ML, Abdelaziz S, et al: Long term risk of cardiovascular disease among colorectal cancer survivors. 2018 Cancer Survivorship Symposium. Abstract 113. Presented February 17, 2018.