Donna Gustafson (left) and her husband, Ed Gustafson. Donna had her first mRNA cancer vaccine seven years ago to treat her pancreatic cancer. Yuki Noguchi/NPR hide caption

Yuki Noguchi/NPR

Donna Gustafson is living a cancer patient's fantasy.

At 72, the retired accountant hikes, travels, lifts weights, and exchanges adoring glances with Ed, the husband she married 50 years ago. All these moments are happening while she shows zero evidence of the Stage II pancreatic cancer that was supposed to kill her years ago.

"I have had 100% quality of life; I am back to where I was prior," Gustafson says.

"She's better than that," her husband interjects. "She's sassier, and she's in the best shape of her life — there's no question about that."

Seven years ago, Gustafson became the world's first recipient of an mRNA vaccine designed to treat pancreatic cancer, a highly lethal disease diagnosed in about 70,000 Americans every year.…