Past radiation therapy amplifies heart surgery’s mortality risk

The long-term death rate for cancer patients who received radiation therapy and who later underwent major cardiac surgery was twice that of similar surgical patients who never had prior radiation. The authors of the study, published April 9 in Circulation, recommended that physicians consider alternative treatments for at-risk patients.

Radiation therapy sometimes is called for to improve the chances of survival in patients with breast cancer, Hodgkin’s lymphoma and other cancers. Years later, the effects of thoracic radiation may manifest as coronary artery, valvular, pericardial or myocardial diseases that require cardiovascular surgical intervention.

“[T]he absence of data on the long-term outcomes of this population, particularly compared with a standard cardiothoracic surgical population, makes decision making especially difficult,” wrote Willis Wu, MD, of the Heart and Vascular Institute at the Cleveland Clinic. To help clinicians better weigh the possible risks and benefits of cardiac surgery, they conducted an observational cohort study that matched 173 patients with a documented history of cancer and chest radiation therapy with 305 patients without radiation. All of the patients received cardiothoracic surgery between 2000 and 2003.

The groups were closely matched in age and gender (63 years old and 75 percent women in the group with radiation-associated heart disease and 63 years old and 74 percent women in the comparison group). The comparison group had a slightly greater preoperative risk and a higher percentage in the radiation group had proximal obstructive coronary artery disease.  The mean duration between chest radiation and surgery in the radiation group was 18 years.

At a mean 7.6 years follow-up, 37 percent of all the patients had died. The mortality rate was much higher in the radiation group, though, at 55 percent vs. 28 percent in the comparison group. Of the patients in the radiation group for whom cause of death was ascertained, 47 died of cardiopulmonary disease while five died of recurrent cancer. The presence of radiation-associated heart disease, increasing EuroSCORE and lack of beta-blockers was associated with increased mortality.

“Our findings suggest that surgical intervention should be applied cautiously to patients who have previously had significant thoracic radiation because the realized survival does not necessarily match what would be expected in a nonradiated population,” Wu et al wrote.  “Survival is even worse in those who have already undergone an open heart surgical procedure.”

The researchers pointed out that the radiation group had a longer postsurgical length of stay and 82 percent underwent multiple surgical procedures. Pulmonary complications after open heart surgery are common in patients who received chest radiation, which may compromise survival, they wrote.

They suggested alternative treatments such as percutaneous transaortic valve replacement, earlier treatment or other future modalities might offer better outcomes.