ADDISON, Texas, Sept. 18 (UPI) -- People between ages 65 and 70 and some treated cancer patients are now candidates for heart transplants, say new U.S. guidelines.

The new rules were co-authored by Stuart Russell, a cardiologist at Johns Hopkins Hospital, and issued by the International Society for Heart and Lung Transplantation (ISHLT).

The guidelines were last updated in 1997, when they restricted access to cancer patients who were tumor-free for less than five years, and who were presumed to have treatment-weakened immune systems that would prevent them from taking anti-rejection drugs.

But the new guidelines allow some people with slow-growing, less-treated cancers to get on the list, and the age cap was raised from 65 to 70 after research found that transplant recipients over age 65 have a 90 percent survival rate one year post-transplant and 50 percent survival at 10 years.

Russell estimated that the inclusions could result in up to 400 more patients in the United States per year qualifying for heart transplants. Since the United Network for Organ Sharing estimates that the demand for transplant organs will probably never be fully met, ISHLT has called for more resources to slow the progression of heart failure and prevent the need for transplant surgery in the first place.

Russell said new drugs, implantable defibrillators and pacemakers, and smaller heart pumps could assist weakened hearts for longer periods, or until a donor organ becomes available.

The new guidelines are posted at http://www.ishlt.org.