George said doctors are analyzing test results at this time and will formulate a plan of treatment. He expects to get the final results next week.
"If this is a call to be with him [God] for eternity, then that is a welcome call in that sense. But it is also a fearful call," he said. "Whatever they find at the end of it they will then say here is the treatment, and I really don't know what that will be."
He said the effects of the procedure left him somewhat weakened, but he has a good appetite and has made no plans for stepping down. The cardinal said he had not yet written to Pope Benedict XVI about his condition.
George said he is relying on prayer as a source of strength during this latest health scare. He also thanked those who have reached out to him with messages of support, especially others who have fought cancer.
"The prayers of so many others are a great blessing to me, and I count on them, and I am grateful ," he said.
George spoke to the press before his appearance at the Hispanic Ministry Awards in Oakbrook Terrace.
Cardinal George turned 75 in January and, as per tradition, submitted a resignation letter to the Pope. He had planned to stay on for two to three years to ensure a smooth transition to his successor.
In 2006, the cardinal underwent serious cancer surgery. His prostate and bladder were removed. He passed the medically relevant third and fifth anniversaries of his surgery in good health leading doctors to believe he was in full remission. But a routine check up earlier this month found cancer had returned to the cardinal's kidney and liver.
George is the eighth cardinal of the Chicago archdiocese and the only one who has lived to see his 75th birthday.