Transcript for 'I'm fighting through it': Alex Trebek discusses cancer battle
A disease that has touched the lives of many. He is the master of the board. In control. Alex trebek! Sophisticated. And seemingly all-knowing. For 35 years and nearly 8,000 episodes, Alex trebek has been the unflappable host of "Jeopardy", making him one of the most enduring and recognizable people on television, even holding a guinness world record for hosting the most episodes of a single game show ever. Let's have some fun. Reporter: But just two months ago he shared heartbreaking Just like 50,000 other people in the United States each year, this week I was diagnosed with stage four pancreatic cancer. Reporter: His announcement was classic trebek. Confident, humorous, poised. I plan to beat the low survival rate statistics for this disease. Reporter: But as he told robin Roberts, battling the disease has been a struggle. How are you? My oncologist tells me I am doing well even though I don't always feel it. I've had kidney stones and ruptured discs, but what I'm not used to are the surges that come on suddenly of deep, deep sadness, and it brings tears to my eyes. Reporter: Even sharing some of his lowest moments. Chemo affects people in different ways. It does. And people have to understand that. And there's nothing wrong with saying, hey, I'm really depressed today, and I have no idea why. Mm-hm. Mm-hm. Been there, done that. Reporter: For trebek, fighting the disease means trying to stay positive while undergoing treatment. I go in, sit down and joke with the nurses, and I'm there for an hour and a half while they inject all of this stuff in me, I go home and have a good day, and the next day for no reason I can fathom, it turns south on me, but that's okay. You have to deal with it, what am I going to do? Reporter: Pancreatic cancer is one of the deadliest kinds of cancer with a five-year survival rate of 5%. Pancreatic cancer is a particularly bad actor, basically because of the location of the pancreas in the body. It's kind of hidden and concealed from a spot where it can be felt as the cancer grows, and typically, it doesn't produce symptoms until it's very advanced. Reporter: It took the lives of Steve jobs, singer and civil rights activist Aretha Franklin. Reporter: Little house on the prairie star Michael Landon, and actor Patrick Swayze who went from "Dirty dancing" heartthrob to being ravaged by the disease. How much weight did you lose? I dropped about 20 pounds in the blink of an eye. Then when you see it in the mirror, all of a sudden you pull your eyes down and the bottom of your eyes go yellow and jaundice sets in, and you know something is wrong. Reporter: He spoke openly about his battle with Barbara Walters in 2009. Are you scared? I don't know. I will be so either truthful or stupid as to say no. But then I immediately when I say that, I have to say yes, I am. I don't know what's on the other side. I love you, lady. I know you do. Reporter: Swayze died less than nine months later, but Alex trebek hopes to beat the odds, joining survivors like Ruth Bader Ginsburg treated in 2009. I've had so many contacts from people who have survived cancer for ten years, 12 years, 14 years. I am now a 30-day cancer I'm going to catch up to those people. Reporter: He has received an outpouring of support. Pancreatic cancer doesn't discriminate. Today it's Alex trebek. But tomorrow it could be someone that you love. Reporter: In Jacksonville, Florida, Judy knows. Stage four is a death sentence. Reporter: The 69-year-old grandmother undergoing treatment for stage four cancer recently wrote a letter to the trivia show host, a man she calls a friend at her home every weekday. I know he's fearful, deep down inside, he's terrified. I know that. Reporter: She says she hoped to encourage him to dig deep into his faith. I believe the only reason I have been able to beat the statistics of 9% who live five years from diagnosis is my faith in god and my positive attitude. Reporter: While the cancer has now spread to her lungs, Judy remains hopeful. Doctors say one of her biggest tumors is almost gone. It's a miracle, it's just a miracle. Reporter: Elysse just might be another medical miracle. I definitely don't take things for granted. Reporter: In 2012 she was diagnosed with stage four pancreatic cancer while raising two young boys. It's devastating to think I might lose my life to this. When I told people I have pancreatic cancer, the first thing they tell you is I'm so sorry. They already put you in the grave. Reporter: Her treatment was aggressive. I ended up doing 12 rounds of a pretty intense chemotherapy. Reporter: Now six and a half years in remission, the 50 year old working mom is sending vibes of hope. Dear Alex trebek. Reporter: Writing an open letter that went viral. I dntsd choose to get cancer, and I didn't choose to go through this, but I do get to choose my attitude, and I choose to be happy, so Alex trebek, go kick cancer's butt. Many people who are living with cancer say it was only when they were diagnosed that they really appreciated the preciousness of life. Reporter: Trebek is continuing to lead as normal a life as possible, and right now that means presiding over one of the most memorable seasons of the show ever. James? What is Paul revere? Reporter: The run is reminding many people of the all-time champ, Ken Jennings. I used to be Mr. Jeopardy but no longer. Reporter: He holds the longest winning streak from back in 2004. What's an elephant seal? You got it. It's really an honor to be compared to Ken at all. But it's interesting. We have different approaches to the game. Reporter: He has won more than $1.5 million so far. How was it for you as a host? It's exciting. It's fun. I watch it almost every night like most of America. He has forced me to change a view that I have held for many years, and that is that the Ken Jennings record would never be broken. Ooh. You love this. Oh, it's exciting. I mean, our ratings are great, thanks to him. But everywhere I go, people are talking about him. Reporter: Trebek is planning to be back at the podium in September, when the 36th season of jeopardy kicks off. I have managed to receive so much love from so many people, and quite often you don't get that during your lifetime. After you're passed, after you're dead, people say oh, he was such a good guy. We really liked him. But I'm getting that all before that event. Mm-hm. So it makes me feel really, really good.
This transcript has been automatically generated and may not be 100% accurate.