Alex Trebek has been diagnosed with stage four pancreatic cancer, he revealed on Wednesday.

The 78-year-old Jeopardy! host announced the sad news on the show's YouTube page.

"Normally the prognosis for this is not very encouraging, but I'm going to fight this, and I'm going to keep working," Trebek says. "And with the love and support from my family and friends, and with the help of your prayers also, I plan to beat the low survival rates statistics for this disease."

"Truth be told I have to, because under the terms of my contract I have to host Jeopardy! for three more years," he jokes. "So, help me, keep the faith, and we'll win. We'll get it done. Thank you."

Trebek has hosted Jeopardy! since 1984, and last October, he renewed his contract to continue hosting the show through 2022.

During his appearance last July on Harvey Levin's show, OBJECTified, he said he could definitely see his life without hosting the beloved game show, and shared that he seriously considered retiring in 2020 before eventually renewing his contract. He even named possible replacements he approves of -- Los Angeles Kings play-by-play announcer Alex Faust and CNN legal analyst Laura Coates.

"If I'm still enjoying it and if I'm not making too many mistakes, then I will continue," Trebek said of his hosting duties. "But there comes a time, of course … [The Price Is Right host] Bob Barker is a perfect example. He was still doing well, but he figured, hey, the time is now. And in life we make a lot of decisions about what we want to do and whether to accept a job, and you should also be able to make an intelligent decision about when it's time to hang things up."

Trebek has dealt with health issues in the past, including suffering mild heart attacks in 2007 and in 2012. Additionally, in 2015 he hosted Jeopardy! seated due to a knee replacement.

Last January, he revealed that he underwent a surgery to remove blood clots on his brain.

"Some of you may have heard that during the holiday break I had a slight medical problem," Trebek said in a video posted by the official Jeopardy! Twitter account. "A subdural hematoma, blood clots on the brain caused by a fall I endured about two months ago."

"Surgery was performed. After two days in the hospital, I came home to start recovery," he continued. "The prognosis is excellent ... And I want to thank all of you for your concern."

Last November, Trebek revealed he was tested for Alzheimer's Disease after experiencing memory lapses.

"The first time they tested me they said, 'It doesn't look good,'" Trebek told Vulture. "Then we did more testing and they said, 'You're OK. No need to worry.'"

"It's natural," he added about not being concerned. "I'm 78. It's not like this happened at 50. When it's clear that it's time for me to go, I'll go."

ET recently spoke to Jeopardy! contestant Brad Rutter, who talked about how the iconic games show host is behind the scenes. Watch the video below for more:

'Jeopardy! All Star': Brad Rutter Reveals What Alex Trebek Is Really Like Off Camera (Exclusive) This video is unavailable because we were unable to load a message from our sponsors.



If you are using ad-blocking software, please disable it and reload the page. Embed Code Restart

RELATED CONTENT:

Alex Trebek Reveals He Was Tested for Early Alzheimer's After Experiencing Memory Lapses

'Jeopardy' Fans Are Loving Alex Trebek's New Beard

Alex Trebek Reveals When He'll Most Likely Retire From 'Jeopardy!,' and Who He'd Want to Replace Him