Alex Trebek Undergoing Chemotherapy Again as He Continues to Battle Pancreatic Cancer

'The thought of passing on doesn’t frighten me,' he told ABC News.

Alex Trebek has had a set back in his battle against cancer.

During Tuesday's episode of of Good Morning America, the 79-year-old Jeopardy host revealed in a taped interview that he's gearing up for another round of chemotherapy following the announcement of his pancreatic cancer diagnosis in March. The latest news came as a surprise, as Trebek said he was "near remission" in May and that some of his tumors had shrunk more than 50 percent.

"My hair started to grow back, but now I have to undergo chemo again, so what little hair I have grown is going to disappear again. In terms of getting my strength back, that hasn't happened unfortunately," Trebek told ABC News' T.J. Holmes of the continuing impact of his diagnosis.

While Trebek said that he "was doing so well" and added that his "numbers went down to the equivalent of a normal human being who does not have pancreatic cancer," that "very optimistic" development did not last long. 

"I lost about 12 pounds in a week and my numbers went sky-high. Much higher than they were when I was first diagnosed," Trebek said. "So the doctors have decided that I have to undergo chemo again and that's what I am doing."

Though Trebek said that he gets "the most optimism" from the fact that he's still her fighting and doesn't "feel terrible," he did not sugar coat the negative impact of his treatments.

"It has different effects on you for some reason, and I don’t understand why. Occasionally it will cause excruciating pain in my lower back. Other times it's fatigue. Other times it's nausea. It varies. Cancer is mysterious in more ways than one," he said. "I am still a bit of a wuss because there are moments when, for no reason at all, I feel this surge of sadness, depression. It does’t last very long, but it just takes over my whole being for a short period of time."

"I understand it more now, so I can deal with it a lot better than I did before. When it happened early on I was down on myself. I said, 'Hey, you shouldn’t be reacting this way,'" Trebek continued. "I didn’t realize how fallible each of us is in his or her own way. I just experience it. I know it is part of who I am and I am going to just keep going."

Despite his continuing battle, Trebek revealed that his remains positive, though he admitted that some aspects of his health struggles do "bother" him.

"I realize that there is an end in sight for me, just as there is for everyone else," he said. "One line that I have used with our staff in recent weeks and months is that when I do pass on, one thing they will not say at my funeral is, 'Oh, he was taken from us too soon.' Hey guys, I'm 79 years old. I’ve had one hell of a good life and I’ve enjoyed it."

"The thought of passing on doesn’t frighten me. It doesn’t," he continued. "Other things do. The effect it will have on my loved ones. Yes, that bothers me and makes me sad. But the thought of myself moving on, hey folks, it comes with the territory."

As for whether he'll put his work on Jeopardy aside -- he returned to the show back in July, while season 36 premiered earlier this month -- to focus on his health, Trebek quickly rejected that idea.

"As long as I can walk out and greet the audience and the contestants and run the game, I am happy," he said.