NO LINK BETWEEN HF AND CANCER RISK

A new analysis of long-term follow-up data from two physician cohorts found no association between heart failure (HF) and incident cancer, despite previous findings suggesting HF is associated with higher cancer risk.

"We wondered whether the association was possibly confounded, for instance, by clinical comorbidities or surveillance bias. Heart failure patients tend to 'bump up' against the healthcare system more, and some cancers may be detected in that fashion," lead author, Senthil Selvaraj, MD, MA, Hospital of the University of Pennsylvania, Philadelphia, told theheart.org | Medscape Cardiology in an email.

"Therefore, we searched for a database that was well equipped to answer the question and had more pertinent cancer data: risk factors, adjudicated outcomes, longer length of follow-up."

The investigators analyzed data from 28,341 male physicians free of either disease at enrollment in the Physicians' Health Studies I and II, two randomized trials of aspirin and vitamin supplements conducted from 1982 to 1995 and 1997 to 2011, respectively.

Over a median follow-up of 19.9 years, 1420 physicians developed HF and 7363 cancers were diagnosed. A median of 3.4 years passed between HF diagnosis and cancer diagnosis in the 177 physicians with both diseases, according to the study, published online ahead of the April 10 issue of the Journal of the American College of Cardiology.

Modeling HF as a time-varying exposure, the results showed no difference in the incidence of cancer among physicians with or without HF in unadjusted analysis (hazard ratio [HR], 0.92; 95% CI, 0.80 - 1.08).

Moreover, the relationship remained nonsignificant after adjustment for enrollment group, race, cigarette smoking, alcohol or aspirin use, family history of cancer, cirrhosis, proton-pump inhibitor or histamine-2 blocker use, and sun exposure (HR, 1.02; 95% CI, 0.84 - 1.25) and after further adjustment for any colonoscopy or sigmoidoscopy, physical exam, rectal exam, and prostate-specific antigen (PSA) testing (HR, 1.05; 95% CI, 0.86 - 1.29).

In an exploratory analysis of site-specific cancers, HF was significantly associated only with prostate cancer (HR, 0.65; 95% CI, 0.50 - 0.84). The relationship, however, weakened after adjustment for enrollment group, race, body mass index, and family history of prostate cancer (HR, 0.74; 95% CI, 0.56 - 0.99) and disappeared after further adjustment for any rectal exam or PSA level tested (HR, 0.78; 95% CI, 0.59 - 1.05).

A secondary analysis of physicians at significant landmark ages also revealed no association between HF and cancer risk.

"I think our results support current practice standards for cancer screening, insofar as HF patients should be screened similarly to the general population," Selvaraj said. "Of course, cancer screening should take into account life expectancy, which may be an important consideration in some advanced HF patients."

"Therefore, cancer screening should be made according to professional society guidelines and involves discussion and evaluation of the individual patient," he added. "What we do not show, conversely, is any increased need for cancer screening among HF patients."

Enough Already?

The results, however, conflict with prior work, including a recent prospective studyin 1081 persons followed for nearly 5 years, in which the adjusted risk for cancer, excluding nonmelanoma skin cancer, was nearly twice as high in patients who developed HF after a myocardial infarction as in those who did not.

Senior author of that prospective study, Veronique Roger, MD, Mayo Clinic, Rochester, Minnesota, told theheart.org | Medscape Cardiology the new report does not put the question of HF and cancer to rest.

"I don't think we have, in part, because larger is not always better and because what you gain in sample size, so to speak, you lose in precision," she said. Also, "it's only applicable to males, by definition."

"While we have to acknowledge that the case is not closed, there are directions for the scientific community and for the lay public," Roger said.

That means ensuring that studies are set up to look at broader sets of outcomes and that shared risk factors between HF and cancer are addressed.