In an interview with ABC News' TJ Holmes, Trebek continued to stay transparent about his battle with stage 4 pancreatic cancer.
"I was doing so well. And my numbers went down to the equivalent of a normal human being who does not have pancreatic cancer. So we were all very optimistic. And they said, 'Good, we're gonna stop chemo, we'll start you on immunotherapy,'" Trebek explained.
But then he lost 12 pounds in a week and his numbers went higher than they were when he was first diagnosed.
"The thought of passing on doesn't frighten me." Watch Alex Trebek's full annoucement about his pancreatic cancer battle.
"So, the doctors have decided that I have to undergo chemo again and that's what I'm doing."
Trebek said cancer is a mysterious disease that takes its toll on people in many different ways.
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"In terms of getting my strength back, that hasn't happened yet, unfortunately."
He went on to say that his cancer sometimes causes him "excruciating pain" in his lower back and other times "fatigue."
Despite the setback, Trebek is not letting cancer keep him down.
"The thing, I suppose, that gives me the most optimism is that, 'Hey. I'm still here, and I don't feel terrible.'"
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The game show host also admitted that he's had to learn to deal with depression. He said he now experiences moments of sadness from time-to-time that "just takes over my whole being for a short period of time."
Still, Trebek, 79, said he had no plans to stop hosting Jeopardy! He has served as the face of Jeopardy! since it made its debut in daytime syndication in 1984. He holds the Guinness World Record for Most Game Show Episodes Hosted by the Same Presenter.
"I realize that there is an end in sight for me, just as there is for everyone else. 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.'" Trebek said. "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. Other things do, the affect it will have on my loved ones ... it makes me sad. But the thought of myself moving on, hey folks, it comes with the territory."