Former heavyweight world champion Leon Spinks is in the intensive care unit at a Las Vegas hospital due to complications from prostate cancer, his family confirmed Friday evening.

Spinks, 66, was diagnosed with prostate cancer earlier this year. The cancer has since spread to his bladder, according to the family statement posted on Twitter:

“Leon is currently in intensive care at a Las Vegas hospital receiving attentive medical care to suppress prostate cancer which he was diagnosed with earlier this year and has since spread to his bladder. The last few months have been an agonizing roller coaster for Leon and his wife, Brenda, with continuous hospital stays. Leon is showing small signs of improvement and progress. A miraculous fighter his entire life, we are optimistic and hopeful that he will move out of ICU soon. The power of prayer is real and his family is beyond grateful for all of the tremendous love and support.”

Brenda Spinks took to Facebook to ask for prayers for her husband.

Spinks won an Olympic gold medal in 1976. In 1978, he scored a major upset by defeating Muhammad Ali in a 15-round split decision to earn the heavyweight championship title. Ali regained the title in a rematch seven months later, ESPN reported. Spinks retired from boxing in 1995 and was inducted into the Nevada Boxing Hall of Fame in 2017, according to ESPN.