A non-smoker who was told he had about two months to live is now nearly three years cancer-free after receiving a double lung transplant through a Northwestern Medicine study.

David Peterson was diagnosed with stage 3 lung cancer after a persistent cough led to testing. The tumor was surgically removed, but the cancer came back and spread to both lungs.

"Nothing was working. I was completely out of options," Peterson said.

Peterson then found Northwestern Medicine's DREAM program. Dr. Ankit Bharat, Chief of Thoracic Surgery at Northwestern Medicine, says there has long been a belief that terminal lung cancer patients should not receive lung transplants, but this study looked at what happens when they do.

"It really is designed to serve as the last option when everything else has failed," Bharat said.

The study included 98 stage 4 lung cancer patients who met certain criteria. Of those, 17 underwent a double lung transplant, while the remaining 81 received medical management alone because a transplant was not an option.

Researchers say 100 percent of transplanted patients were alive one year after surgery, compared to a 41-percent one-year survival rate among patients treated with medical therapies alone.

"It offers the possibility of hope to many, many hopeless patients," Bharat said.

Peterson had been told he had about two months to live before the transplant. Nearly three years later, he remains cancer-free with no signs of organ rejection.

"Don't give up," Peterson said.