Ryan O'Neal's Chance for Cancer Cure 'Relatively Small,' Doctors Say

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Ryan O'Neal's cancer prognosis may not be as sunny as he initially claimed.

Late last week, the actor told People magazine that he's been diagnosed with stage four prostate cancer, but because it was detected early, his doctors believe the "prognosis is positive for a full recovery."

Doctors told ABCNews.com that doesn't compute.

"It's peculiar, stage four is not early," said Dr. Herbert Lepor, a urology professor at the NYU School of Medicine. "Let's say this is metastatic prostate cancer. That is a fatal disease. It's the second most common cause of cancer deaths in men."

"Stage four prostate cancer is normally very advanced," said Dr. Leonard Gomella, a professor of prostate cancer at Thomas Jefferson University. "It likely means it has spread to his lymph nodes, his bones, other parts of his bodies. He's going to have systemic therapy. The chance for a cure is relatively small."

Lepor said O'Neal's doctors are likely treating him with hormones, which means that they won't necessarily rid his body of cancer. "To think that you're getting a full recovery," he said, "that's not the case."

Lepor said its possible that O'Neal wasn't getting regular prostate screenings, which would account for discovering the cancer at the stage four level. In his statement to People, O'Neal advised fans to get regular check ups, "as early detection is the best defense against this horrible disease that has afflicted so many."

O'Neal, 70, is prearing for the May 1 release of "Both of Us," his memoir about his late partner, Farrah Fawcett. She died of anal cancer in 2009.