"Jeopardy!" host Alex Trebek announced he has stage 4 pancreatic cancer. "Now normally, the prognosis for this is not very encouraging, but I'm going to fight this, and I'm going to keep working," he said in a video published Wednesday to his YouTube channel.

Trebek, 78, said he was aware of the low survival rates, but he said in a lighter tone that he still has three years left on his contract.

"And with the love and support of my family and friends and with the help of your prayers also, I plan to beat the low survival rate statistics for this disease," Trebek said. "So help me. Keep the faith and we'll win. We'll get it done. Thank you."

Pancreatic cancer is the the third leading cause of cancer-related death in the United States, killing more people than breast cancer, according to the American Cancer Society. Rates are rising faster than any other cancer in the country.

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One of the reasons pancreatic cancer is so deadly is that no early screening test — nothing like the mammogram for catching breast cancer or the colonoscopy or stool test or detecting colon cancer. And there is no cure. The very nature of it makes it difficult to study, say experts.

Pancreatic cancer researcher Dr. Sunil Hingorani told CBS News in 2017 that the disease is "highly and also rapidly lethal."

The speed at which the disease spreads also makes it difficult to find and retain patients for clinical trials and other studies that would help researchers learn more about the disease.

"It's very traumatizing, of course, to the patient, but also to their families. There's little time to absorb the diagnosis before a patient ends up succumbing to the disease," said Hingorani, a faculty member at Fred Hutchinson Cancer Research Center in Seattle and professor at the University of Washington School of Medicine.

"With pancreatic cancer, it's a little bit of a Catch-22. That also is part of its challenge for clinicians and scientists who study it. It's been relatively understudied and underfunded because of this sense of futility," he said.

For now, he said, "Hope and optimism are the most you can offer a patient."

Sony Pictures Television chariman Mike Hopkins said Trebek has their "full support as he tackles this challenge head-on."

"If anyone can beat this, it's Alex," Hopkins said.

Mary Brophy Marcus contributed to this report.