(CNN) -- Joe Paterno, the Penn State football coach who lost his job amid allegations of child sex abuse against his former defensive coordinator, has a treatable form of lung cancer, his son said Friday.
The family learned of the diagnosis after Paterno's follow-up visit last weekend for a bronchial illness, Scott Paterno said.
"He is currently undergoing treatment, and his doctors are optimistic that he will make a full recovery," Scott Paterno said in a statement. "As everyone can appreciate, this is a deeply personal matter for my parents, and we simply ask that his privacy be respected as he proceeds with treatment."
Paterno, 84, the all-time winningest football coach in Division I history, was fired last week amid the outcry over the handling of the abuse claims.
Treatment options include surgery, chemotherapy and radiation, CNN senior medical correspondent Elizabeth Cohen said.
"It is such a difficult, difficult cancer to beat," she said. "Often, it is found pretty late."
Cohen said that catching the disease early is crucial to improving chances for survival. White men who discover their lung cancer early have a 50-50 chance of being alive five years later. If they catch it late, they have a 4% chance of being alive five years later, Cohen said.
If Paterno is a candidate for surgery, Cohen told "The Situation Room," he may lose at least 20% of his lungs.
Paterno, who served 46 years as head coach in State College, was known to generations of football fans simply as JoePa.
National outrage percolated over Paterno's reaction to a graduate assistant's 2002 report that he had seen former Penn State defensive coordinator Jerry Sandusky performing anal sex on a young boy in the shower room of the football complex.
Paterno said that he'd never been told the graphic details revealed in a grand jury report about sex abuse allegations but that he nevertheless passed the allegations on to his boss. He said he had done "what I was supposed to do." In a later statement, he said "with the benefit of hindsight, I wish I had done more."
It was years before law enforcement learned about the allegation.
Friday's announcement coincides with news of an NCAA investigation at Penn State.
"This unprecedented situation demands the NCAA evaluate the university's accountability" and application of NCAA bylaws, NCAA President Mark Emmert said in a letter to the school.
CNN contributor Sara Ganim reported from Pennsylvania.