"I wanted to once again thank you for your continuing messages of encouragement and support, particularly the many cards I've received from young people," he said in the April 17 video. "I'm touched beyond words."
Related: 'Jeopardy!' host Alex Trebek diagnosed with Stage 4 pancreatic cancer
“I’ve had so many contacts from people who have survived cancer,” he told Roberts. “I am now a 30-day survivor. ... I’m going to catch up to those other people.”
Still, chemotherapy has been tough on the 78-year-old, but, just as he did when he revealed his diagnosis, Trebek is remaining humorous about it.
“My oncologist tells me I’m doing well even though I don’t always feel it,” he said. “I’ve had kidney stones, I’ve had ruptured discs, so I’m used to dealing with pain, but what I’m not used to dealing with is the surges that come on suddenly of deep, deep sadness and it brings tears to my eye. I’ve discovered in this whole episode, ladies and gentlemen, that I’m a bit of a wuss.
“But I’m fighting through it. My platelets, my blood counts are steady, my weight is steady. … The cancer indicators, those are coming down. So I’ve got another chemo next week, and then we’ll do a review to find out where things stand.”
Related: Alex Trebek says he's 'feeling good' after cancer diagnosis, wraps taping season 35 of 'Jeopardy!'
He also offered encouragement to others going through chemotherapy.
“Chemo affects people in different ways and people have to understand that, and that there’s nothing wrong with saying, ‘Hey, I’m really depressed today and I don’t know why,’” he said.
“You have to deal with it. What am I gonna do?" he said. “It’s something I am afflicted with, we are dealing with it chemically and spiritually, and those are positive. Hopefully, everything is going to turn out well and I'll be back on the air with original programming this September.”
Watch Trebek’s “GMA” interview below.