12:11 PM PT -- Alex is clarifying the quote from his book about stopping cancer treatment if it does not continue to work. He says it was written before his current regimen, when he was "going through some bad times," and if his treatment stops being successful now ... he would return to his previous chemo treatment -- not stop all treatment.
He adds ... "I apologize for any confusion, and want everyone to know that I am optimistic about my current plan, and thank them for their concerns."
Alex Trebek -- the beloved host of "Jeopardy!" for 36 years and counting -- has reached a new major milestone ... celebrating his 80th birthday.
Alex has turned 80 on the heels of the release of his new memoir, "The Answer Is...: Reflections On My Life," and during a constant battle with stage 4 pancreatic cancer after being diagnosed last year.
Through it all ... Trebek has been legendary, continuing to host the game show while receiving treatment and providing inspiration to millions of others battling cancer.
Alex opened up this week, saying he is undergoing experimental cancer treatment and this will be his last ... he's already undergone other treatments that have been difficult, and he says he's discussed it with his family and it all came down to a quality of life decision.
And, even after 36 years and 8,132 episodes, Alex says he plans to continue his "Jeopardy!" gig as long as he's around. When he eventually must be replaced, he recently joked with 'GMA' that the perfect person for the job is ... his longtime friend, Betty White.
All kidding aside, Trebek revealed back in 2018 who he really has in mind to replace him -- a fellow Alex ... L.A. Kings play-by-play announcer, Alex Faust, and CNN contributor and attorney Laura Coates. BTW ... don't discount Anderson Cooper.