Patients who have open heart surgery for heart disease caused by radiation cancer treatment are nearly twice as likely to die in the years following their surgery compared to similar patients who did not undergo radiation treatment, according to new research from Cleveland Clinic published today in the American Heart Association journal Circulation.
The team of researchers, led by Milind Desai, M.D., a cardiologist in the Sydell and Arnold Miller Family Heart & Vascular Institute at Cleveland Clinic, examined 173 patients who underwent heart surgery an average of 18 years after receiving chest radiation for cancer and compared the mortality rates to 305 similar heart surgery patients who did not undergo prior radiation. After an average follow-up of 7.6 years, 55 percent of the patients in the radiation group had died, compared to 28 percent in the non-radiation group. Short-term mortality (including 30-day mortality) were not significantly different. In the cases where cause of death could be ascertained, the vast majority died as a result of heart or lung disease and not from recurring cancer.
"Even with low-risk scores and procedural success, chest radiation years or even decades prior to heart surgery puts patients at a much higher risk for long-term events," said Dr. Desai. "Further research needs to be done to understand this patient population and to better stratify their risk so that we can identify the most effective ways to treat their complex disease."
Radiation therapy is often the most effective way to treat cancers that affect the chest, including cancers of the breast and lung, and Hodgkin and non-Hodgkin lymphoma. But radiation can cause problems for the heart and its surrounding structure that often manifest themselves years, even decades, later. Long term, chest radiation can cause coronary artery disease, valve disease, cardiomyopathy -- or weakening of the heart muscle -- and problems with the electronic signals that make the heart beat.
"In radiation heart disease patients, we often see a very peculiar presentation of cardiac disease," Dr. Desai said. "These are often younger patients than typically present with advanced heart disease, and they often have aggressive coronary artery blockages, valve narrowing or leakage -- in many cases involving multiple valves -- and thickening of the sac around the heart."
The researchers say that it's important for physicians to recognize when the heart disease is caused by radiation and then decide on the best strategy to treat these patients.
"Not all of these patients are at the same level of risk – there is a spectrum of risk," Dr. Desai said. "We need to develop ways to identify the risks and better determine which patients would benefit from surgery versus other treatments, like percutaneous interventions, for example."
Dr. Desai said it's important for cancer patients who receive chest radiation to know the risks to their hearts and be aware that they could encounter heart disease down the road.
"If you have had prior chest radiation and you are now experiencing heart problems, the two could be linked," he said. "It's vital that you discuss it with your doctor and find a treatment center experienced in treating patients with radiation heart disease – one that has doctors who understand the disease and have the expertise to diagnose and effectively treat it."