The situation was so grim, doctors didn't even expect Challis to make it through that first summer.
However, Challis has been able to beat the odds, and has spread his message of courage to the entire nation. He has spoken at high school assemblies, talked on radio broadcasts and has appeared on a number of television stations.
That's how Challis grabbed Maddon's attention, when ESPN broadcasted the story of Challis' first varsity baseball hit on April 11.
"I was so impressed by his line-drive single to right field," Maddon said. "Someone with a cell phone took a photograph of him hitting. You see this perfectly level swing, body balance, etc.
"I heard the entire story. I knew that where he was from was near this area, so I wanted to invite him out to meet our guys."
On Saturday, Challis, who was the Pirates' special guest on Wednesday, was given his own Rays jersey with his name and No. 11 printed on the back. He had a chance to walk through Tampa Bay's clubhouse and meet with players as well.
"It's awesome hanging out with these guys," Challis said. "I watch these guys on ESPN, and they say that they've seen me on ESPN. It really puts it in perspective for me."
Maddon and the Rays' management had a poster made with Challis' motto printed on it. It reads, "Courage + Believe = Life." Every Rays player signed the poster in honor of Challis.
"God let's everything happen for a reason," Challis said on Wednesday. "My reason is he thinks I'm strong enough to handle it, so he's using me to spread his message to make the best of things out of life. Pretty much all I'm doing is making the best of things in life."
Challis has even started his own foundation that is geared toward helping high school student athletes with terminal diseases.
"We just want to help kids," Challis said. "It's a smaller version of Make-A-Wish."
Challis was asked on Saturday afternoon what the most special moment of the week has been.
"I'm going to have to say how friendly all the coaches on all the teams have been," Challis said. "[Starting with] the Pirates, the Yankees and now the Devil Rays."
Maddon interrupted, "You owe me a dollar. We're the Rays. We're no longer the Devil Rays."
"Since when?" Challis said.
"Since this year," Maddon answered, "so before you leave, you owe me a dollar."
So Challis found a dollar bill, signed it and gave it to Maddon.
"I want a memo next time," Challis said.