At an event for Newcastle United, where Keegan both played and coached, the former international striker and England captain said his doctor had told him a new treatment had produced fantastic results - that it had helped in 33 percent of cases.
"33 percent! I thought it would be 80, 90 percent. But I'm still here," Keegan said, according to the BBC.
Keegan, 74, was diagnosed with cancer in January. He now says the cancer is stage four, meaning it has spread throughout his body.
He was awarded the Ballon d'Or, the award for the world's best player, twice in the 1970s and won several titles with Liverpool.
