No early cancer risk with donor lungs from heavy smokers



LOS ANGELES – Use of lungs from donors who smoked heavily does not worsen lung transplantation outcomes including risk for lung cancer death, at least in the medium term.

At a median follow-up of 2 years for 5,900 adults who had double-lung transplants, those who received lungs from heavy smokers had an actuarial median overall survival of roughly 5.5 years, and their lung function was essentially the same as that of patients who received lungs from other donors, Dr. Sharven Taghavi reported at the annual meeting of the Society of Thoracic Surgeons.

Dr. Sharven Taghavi

The study data came from the United Network for Organ Sharing (UNOS) database. A team led by Dr. Taghavi, of Temple University Hospital in Philadelphia, compared data for double-lung transplants from 2005-2011, comparing donors with a history of smoking exceeding 20 pack-years with other donors.

About 13% of the study patients received lungs from donors who had smoked heavily. Compared with other recipients, these recipients were more likely to have a primary diagnosis of chronic obstructive pulmonary disease and less likely to have a diagnosis of idiopathic pulmonary fibrosis. Otherwise, they were similar.

The rate of deaths due to cancer was based on case reports, as UNOS does not capture this outcome. Cancer deaths were 5.8% among recipients of lungs from heavy smokers and 3.6% among other recipients.

"There is a fairly low capture rate for this field, so it’s difficult to draw significant conclusions from it," cautioned Dr. Taghavi.

Patients who received lungs from heavy smokers had a 1-day longer length of stay in the hospital (18 days vs. 17 days), which "may not really be clinically relevant." Rates of acute rejection during hospitalization were comparable (10.7% vs. 8.8%), as was post-transplant airway dehiscence (1.8% vs. 1.8%).

Post-transplant peak forced expiratory volume in 1 second (FEV1) was the same (80% vs. 79%), as was decline in this measure over time. Median duration of freedom from bronchiolitis obliterans syndrome was 1,583 days vs. 1,827 days.

Risk-adjusted median all-cause survival – the study’s primary endpoint – did not differ significantly between the recipients given lungs from donors who smoked heavily and the other recipients (2,043 vs. 1,928 days).

The rate of cancer deaths did not differ significantly; however, the follow-up time is too short to address this concern in a meaningful way, Dr. Taghavi said.

"Currently, we recommend when evaluating a donor who has a heavy smoking history, that they undergo a thorough examination for lung tumors or evidence of cancer. This includes obtaining a chest x-ray, CT scans, and bronchoscopies. In addition, when the lungs are procured, they should undergo a very thorough visual inspection," he advised.

"Informed consent is very important. You have to discuss the donor’s smoking status with the recipient and explain the risks and the benefits," Dr. Taghavi said. Lung cancer risk, given the donor’s history, is about 1% to 2% annually, and that needs to be considered against the high likelihood of dying within 1 or 2 years without a transplant.

"One thing that is unquestionable is that survival will be better accepting these lungs than it will be sitting on a waiting list," he added. Only about half of the people listed for lung transplant in the United States each year actually undergo the surgery.

Recipients of lungs from heavy smokers do not need any extra follow-up or surveillance, as they are already diligently tested and monitored, according to Dr. Taghavi. The recipient’s immunosuppression does theoretically put one at additional risk for lung cancer.

Current guidelines of the International Society of Heart and Lung Transplantation advise against considering use of lungs from donors who have a smoking history of more than 20 pack-years, Dr. Taghavi noted. But he stopped short of saying that the study should prompt a formal revision of those guidelines.

"I think the findings start the conversation," he commented. "We should consider looking at these potential donors," especially when a recipient’s situation is dire.

Dr. Taghavi disclosed no conflicts of interest.

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