Seve Ballesteros' brain tumor: How deadly?

(CBS/AP) Seve Ballesteros earned fame battling other golfing greats on the pro tour, but in recent years the 54-year-old Spaniard has been engaged in a different sort of fight.

He's been battling a brain tumor - and the fight isn't going well.

"The Ballesteros family informs that Seve's neurological condition has suffered a severe deterioration," a statement on the golfer's website said. "The family will inform accordingly about any change in his health condition and takes this opportunity of thanking everyone for the support that both Seve and his own family have been receiving during all this time."

Ballesteros - winner of two Masters and three British Opens - is being cared for at home in the northern Spanish town of Pedrena, his family said. He's been recovering since having four operations in late 2008 and undergoing chemotherapy.

Along with radiation, surgery and chemo commonly used to treat brain tumors, which last year struck 22,020 Americans and killed more than 13,000. So far, doctors have had trouble identifying specific risk factors for brain tumors, according to the American Brain Tumor Association. Various potential factors have been studied, but only radiation exposure and some rare hereditary conditions have consistently been shown to increase risk.

Ballesteros is suffering from an oligoastrocytoma, Sports Illustrated reported in 2008. That's a form of brain tumor that arises in the so-called glial cells that protect nerve cells in the brain and spinal cord, according to the association's website. Symptoms include seizures, headaches, and personality changes.

Ballesteros has made few public appearances since March 2010. He looked thin and pale during appearances in 2009 after being given what he referred to as the "mulligan of my life."

Hopefully for the golfer and his fans, that do-over isn't over.

The National Cancer Institute offers more on brain tumors.