John Daly Has Surgery to Treat Bladder Cancer, 85% Chance It Returns

Golf legend John Daly says he has undergone a procedure to treat bladder cancer ... but doctors told him there's a high probability it returns.

54-year-old Daly -- who famously won the PGA Championship in '91 -- says he had been battling back pain and kidney stones in recent weeks.

But, after he passed the stones, Daly was still experiencing pain and doctors ultimately determined he had cancer.

"[The urologist said] it doesn't look like any stones are in there. But unfortunately, you have bladder cancer," Daly told the Golf Channel.

"After I did the CT [scan] I was fixing to sip on my Diet Coke and he said, 'Don't drink anything. We have to get you back in here and get this cancer out of you.'"

Daly says he's already had a surgery to remove the cancer -- but doctors say the fight is far from over.

"[The doctor] said there's an 85% chance it comes back. So, I've got to go back and see him in 3 months. They will probably have to cut it out again," Daly said.

"It's probably going to come back, and then another 3 months that you don't know. You just don't know. Luckily for me, they caught it early, but bladder cancer is something that I don't know all the details. But, it doesn't look like it may go away. We will just see what happens. Maybe, there's a miracle."

Daly says he will fight hard -- and will even change his diet and smoking habits as a result of the diagnosis.

"I'm cutting way, way back on the Diet Coke and counting minutes before I can have a cigarette. I'm trying to quit smoking," Daly said.