ALPHARETTA, Ga. -- Days after doctors told Connor McMahon that he was cancer-free, his Atlanta Fire hockey teammates held a surprise party for him at The Cooler in Alpharetta.
"It was a good surprise," Connor told 11Alive's Jennifer Leslie. "I'm feeling great. It's good to be home."
"It's just hard to believe this whole thing is over," Connor's dad, Don McMahon, said.
Connor spent six weeks at Duke Children's Hospital to take part in a national clinical trial of CAR T-cell therapy, which used a disabled form of HIV to modify his immune system and attack cancer cells.
Doctors warned Connor and his family that the procedure would take a toll on his body.
"There were some incredibly difficult days when you think you're going to lose your son," Don explained. "It's a pretty powerful moment."
Connor's temperature shot up to 107 degrees for several days.
And then, the fever broke so the healing could begin.
"I don't really remember much of it," Connor said.
When Connor had acute lymphoblastic leukemia twice before, at the age of 3 and 12, he went into remission after intensive chemotherapy.
But his third diagnosis over the summer proved his cancer was resistant to the treatment long-term.
That's why there was so much riding on the T-cell therapy.
"Eventually, his body will make all the healthy cells again, and this becomes a thing of the past," Don added. "Hopefully this can become the cure for the future."
The day before Thanksgiving, Connor joined his teammates on the ice for the first time since returning from Duke.
They gave the hockey goalie a special welcome back by tapping the ice with their sticks.
Connor isn't finished with hospitals yet.
He'll have to go back twice a month to have his blood checked. He'll also require b-cell supplements.