"Heart failure patients are not only at an increased risk for developing cancer, but the occurrence of cancer increases mortality in these patients," explained Dr. Veronique Roger, MD, director of the Mayo Clinic Center for the Science of Health Care Delivery and co-author of the study. "These findings underscore the importance of cancer surveillance in the management of heart failure patients."

Researchers conducted the study using medical records from the Rochester Epidemiology Project, which links the inpatient and outpatient records from all providers used by the population of Olmsted County, Minn. The study included 596 patients with heart failure paired with the same number of similar healthy subjects.

The study looked at two 11-year time periods. Patients diagnosed with heart failure between 1979 and 1990 had a 48 percent increased risk of cancer, while patients diagnosed between 1991 and 2002 had an 86 percent increased risk. Roger and colleagues suggest several possible causes for the increased risk of cancer in heart failure patients, including side effects of cardiovascular treatments, or stress from illness or other mechanisms associated with the physiology of heart failure such as inflammation.

Investigators stress the importance of the findings in the treatment and management of heart failure, concluding patients should be monitored closely for signs of cancer.

"These findings also illustrate the importance of multi-morbidity among patients living with chronic diseases and support the concept of providing holistic rather than disease-based care," the authors said.