MI Patients Who Develop Heart Failure Vulnerable to Higher Risk of Cancer

Among MI patients, those who develop heart failure after their event face a much higher risk of developing cancer than those who don’t, according to an observational study. The study, published in the July 19, 2016, issue of the Journal of the American College of Cardiology, highlights a number of potential shared risk factors associated with both heart failure and cancer.

“Management of patients with CVD or any other form of disease really needs to be holistic. Patients very seldom, if ever, present with one single disease,” senior author Veronique Roger, MD (Mayo Clinic, Rochester, MN), told TCTMD, stressing the importance of “multimorbidity.”

The analysis follows another study by the same researchers, published 3 years ago in JACC, showing that people with heart failure in general had a greater risk of getting cancer than other individuals living in their community. But there were concerns that there might be unmeasured factors influencing differences in either the occurrence of cancer or its detection between the two cohorts.

So this time, the investigators narrowed their focus on MI patients who did versus did not develop heart failure. Importantly, they say, these two groups “share a common disease mechanism (atherosclerosis), risk factor profile, treatment modalities, and follow-up routines.”

Finding Connections With Cancer

Roger and her colleagues used data from a perspective cohort study carried out in Olmstead, MN, from 2002 to 2010. The study involved more than 1,000 people who had experienced an MI and excluded anyone with a prior diagnosis of heart failure or cancer. Participants were followed for a mean of 4.9 ± 3 years. In total, 228 MI patients developed heart failure and 98 developed cancer.

The incidence density rates for cancer diagnosis was 33.7 per 1,000 person-years for MI patients with heart failure and 15.6 per 1,000 person-years for those without (P = 0.002). Cancer risk was nearly doubled for the heart-failure group (HR 2.16; 95% CI 1.39-3.35), and the added risk remained after adjustment for age, sex, and Charlson comorbidity index (HR 1.71; 95% CI 1.07-2.73).

A cancer diagnosis sharply increased mortality risk whether the MI patients did or did not have heart failure (HR 3.91 and 4.90, respectively; P for interaction = 0.76).

The Causation Gap

The correlation between heart failure and cancer risk found in the study raises many questions about possible mechanisms. In an accompanying editorial, Jyoti Malhotra, MD (Rutgers Cancer Institute of New Jersey, New Brunswick), and Paolo Boffetta, MD (Icahn School of Medicine at Mount Sinai, New York, NY), are quick to rule out the idea that heart failure itself is the culprit.

“As the average follow-up period for this study was 5 years, and the median time from MI to cancer diagnosis was 2.8 years, it is unlikely that heart failure is playing a causative role in carcinogenesis, because cancer has a latent period of at least a few years from the time of exposure to the risk factor,” Malhotra and Boffetta write.

The editorialists do allow that it is still possible that heart failure plays a role in later stages of cancer development. This is an opinion shared by Gregg Fonarow, MD (Ronald Reagan UCLA Medical Center, Los Angeles, CA), who says the study highlights that particular point well.

“It really does suggest that the processes involved after heart failure occurs may be increasing the risk of cancer developing, or at least cancer becoming clinical evident,” Fonarow, who was not involved in study, told TCTMD.

Shared risk factors of heart failure and cancer—such as smoking and obesity—could also be noteworthy to uncovering the direct connection between the two, according to Fonarow. 

“Physical inactivity, which is a risk factor for CVD, has also been associated with the development of cancer. So we really see there are these common links between these common lifestyle factors and exposure factors between heart disease and cancer,” he said. “But here’s a circumstance where developing heart failure seems to lead to individuals being at subsequently higher risks for cancer becoming clinically manifest.”

Roger agreed that these factors must be part of the answer for why heart failure patients were at higher risk of cancer, adding that the burden of other chronic diseases is potentially another element.

Another possibility, the researchers note in their paper, is that specific cardiovascular medications, such as angiotensin-receptor blockers, cardiac glycosides, diuretic agents, statins, and prasugrel, might be linked to cancer risk. While it is hard to know for sure, given that the patients as MI survivors tended to be on many of the same drugs whether or not they had heart failure, “there was no indication that treatment was associated with an increased risk of cancer," they say.

No Added Screening Needed

The study provides ample reason to consider the links between diseases, the editorialists say, but they express reservations about what these might mean for clinical practice.

“An important clinical question that arises from these results is whether patients with [heart failure] warrant more cancer screening testing than the population at large,” Malhotra and Boffetta write. “It is interesting to note that although the number of cases in each group was small, the most frequent cancers in patients with [heart failure] were respiratory and digestive cancers for which we do not have routine screening tests (except for low-dose CT scans in heavy smokers for lung cancer).”

While Fonarow agreed that the study does not make a case for more screening, he said it does carry a message unique to heart failure patients.

Thanks to better treatments becoming available, “patients with heart failure are living longer,” Fonarow said. Clinicians too often focus on heart failure alone, meaning “that general health maintenance and cancer screening can fall to the wayside and can be deprioritized.”

This shouldn't happen, he advised. Rather, screening guidelines should be followed just closely in a heart failure patient as they would be normally.

Michael H. Wilson is the 2016 recipient of the Jason Kahn Fellowship in Medical Journalism.

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• US and European Heart Failure Guidelines Advocate Use of Two New Therapies
• CAD Extent May Foreshadow Risk of Heart Failure After First MI