Dan Fogelberg, the Peoria-born pop singer (so, in Illinois) who has sold more than 20 million albums over the past four decades, is undergoing experimental medical treatment to combat advanced prostate cancer.

"We're all very hopeful," said his mother, Margaret Fogelberg of Peoria. "But we're also a bit leery."

Fogelberg this week canceled a 16-city solo acoustic tour of the East Coast and Florida. His Web site, DanFogelberg.com, has issued a short statement that says in part:
"Dan has been recently diagnosed with advanced prostate cancer and has entered treatment. He apologizes for any inconvenience the cancellation of the concerts may cause his fans. Dan is confident he will be able to fight this illness. Your prayers, good wishes and positive thoughts will be very much appreciated."

Dan Fogelberg, who turned 53 last week, was tested for prostate cancer two years ago during a routine checkup, and the results were negative, his mother says. Two months ago, in gearing up for the planned tour, he underwent another checkup, during which the cancer was detected.

Dan Fogelberg, who has lived in Colorado for more than two decades, shared the results with his mother and his wife, Jean - but almost no one else. At the time, he told his mother, "I've had a lot of wonderful fans. I don't want to alarm them until I have more information."

Further testing showed the cancer has spread to his bones, his mother said. So Dan Fogelberg and his wife headed to Harvard Medical School, where doctors have embarked on an experimental regimen.
Margaret Fogelberg said she did not know the technical particulars of his treatment. But she did say he first was put on hormone therapy and a nutrition program.
Recently, he started a new form of chemotherapy: "It's not the kind that tears you up," his mother said.

So far, the results have been positive, and Dan Fogelberg has felt good enough to go sailing with his wife near his second home in Maine, his mother said. However, the stress of the treatment and the uncertainty of his prognosis prompted him to cancel the fall tour.
"The doctors told him he won't be a victim or a survivor. They won't classify people as that," his mother said. "He'll be a patient, and he'll have a good quality of life... He's handling it. He has bad days and good days. I'm sure there are days he's scared half to death."

In the wake of his diagnosis, Dan Fogelberg and his wife hope to raise money for cancer research. As for plans to perform again, Dan Fogelberg has made no decision.
"He has relatives saying he's got to perform one more time, we need to hear him one more time," Margaret Fogelberg said. "So, with that kind of pressure, maybe he will."

The son of Margaret and Lawrence Fogelberg, Dan Fogelberg graduated from Woodruff High School and the University of Illinois at Urbana-Champaign.