Swayze said that in the year since his diagnosis, he had defied the statistics and "trash magazines" that predicted he should have "already been dead a long time," but he acknowledged that time may be running out.
"I'd say five years is pretty wishful thinking," he told Walters. "Two years seems likely if you're going to believe statistics. I want to last until they find a cure, which means I'd better get a fire under it."
The 56-year-old actor said he's waging his battle against cancer "moment to moment."
"When do you decide the fight isn't matching up to your quality of life?" he asked. "So far, I've got potential for a lot of quality of life."
Swayze responded well to his first round of chemotherapy, but as is common, that treatment eventually became less effective, so he recently began a new therapy.
"You can bet that I'm going through hell," Swayze said, but he vowed to keep fighting.
"I'm at the beginning of my battle. And I expect it to be a long hard battle, one that I'm gonna win according to certain rules … the rules that the cancer isn't going away. Now, mind you, I keep my heart and my soul and my spirit open to miracles. I pray."
Asked if he was scared, Swayze told Walters, "I don't know. I will be so either truthful or stupid as to say no. But then I immediately, when I say that, I have to say yes, I am."
Swayze's battle with cancer began late in 2007. As he celebrated New Year's Eve with his wife, Lisa Niemi, Swayze felt that something was wrong.
"I tried to have champagne, and it would be like pouring acid, you know, on an open wound."
And soon it got worse.
"My indigestion issues got gigantic and constant. And then I started thinking, 'I'm getting skinny. I dropped about 20 pounds in the blink of an eye.' And then when you see it in the mirror, when all of a sudden you pull your eyes down and the bottom of your eyes go yellow and jaundice sets in -- then you know something's wrong."
Swayze realized that he needed medical attention. "I started doing a little research and started realizing this is not pretty. This is not a good thing."
Doctors found that the actor had a malignant tumor in his midsection, and a tiny mass on his liver. Pancreatic cancer is extremely difficult to diagnose, and only after a battery of procedures over several days were his doctors able to make a definitive diagnosis: stage 4 pancreatic cancer.
It fell to Niemi, 52, to break the news to her husband.
"It was very surreal," she said. "They were like 99 percent sure. And I know he was still a little dopey from the procedure and I could have told him then, and I said you know what, this is information he can do without for just a few hours, 'cause after he learns this, we can't go back. So I waited until the next morning to tell him about it, and for the first few weeks it was like being in a nightmare you couldn't wake up from."
Although the majority of patients with advanced stage pancreatic cancer die within six months of the diagnosis, Swayze reacted with defiance.
"I have the meanness and the passion to say, 'To hell with you. Watch me! You watch what I pull off.'"