"Jeopardy!" host Alex Trebek announced Wednesday he has stage 4 pancreatic cancer. Trebek, 78, said he was aware of the low survival rates, but remained optimistic.

"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 on his YouTube channel.

He joked that he still has three years left on his contract, and added, "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."

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Those statistics are, indeed, grim. According to the American Cancer Society, nearly 57,000 people in the U.S. will be diagnosed with pancreatic cancer this year and more than 45,000 will die from the disease.

Pancreatic cancer is the 10th most commonly diagnosed cancer in men in the United States, and the ninth most common in women. It accounts for about 3 percent of all cancers but about 7 percent of all cancer deaths, and is one of the deadliest forms cancer.

What does stage 4 pancreatic cancer mean?

Like with other cancers, pancreatic cancer is categorized by stages which describe how far the cancer has spread and how much of the body it has affected.

In stage 1 and some forms of stage 2 pancreatic cancer, the cancer is contained to the pancreas — an organ in the abdomen that helps regulate blood sugar and digestion.

In other forms of stage 2 and stage 3 pancreatic cancer, the cancer has spread to nearby sites like lymph nodes or blood vessels.

By stage 4 — the most severe — the cancer has spread to distant sites of the body like the liver, lungs, or bones.

What is the survival rate for pancreatic cancer?

The five-year survival rate for pancreatic cancer is just 9 percent, making it the lowest survival rate among all the major cancers.

When looking at the survival rate for stage 4 pancreatic cancer, the statistics are even worse. Just 3 percent of people with stage 4 pancreatic cancer will still be alive after five years.

However, it's important to note that these numbers are based off historical data and there have been some advancements in the treatment options available today, so new patients may have a better outlook than these numbers show.

What are the warning signs of pancreatic cancer?

A big part of the reason why pancreatic cancer is so deadly is that it's difficult to detect early. By the time it's diagnosed, the cancer is usually late stage and hard to treat.

The early symptoms of pancreatic cancer are non-specific and often benign, so many patients don't notice or realize something is seriously wrong.

Warning signs of pancreatic cancer may include:

Pain, usually in the abdomen or back

Weight loss

Jaundice (yellowing of the skin, eyes or both), with or without itching

Loss of appetite

Nausea

Changes in stool

Pancreatitis (swelling of the pancreas)

Recent-onset diabetes

Julie Fleshman, president and CEO of the Pancreatic Cancer Action Network (PanCAN.org), urges people to know these early warning signs.

"If you have more than one of those symptoms, you should talk to your doctor about pancreatic cancer," she told CBS News.

This is especially important for people with risk factors that may make them more likely to get pancreatic cancer. These include a family history of pancreatic cancer or other cancers, chronic and hereditary pancreatitis, diabetes, obesity, tobacco use, and a poor diet.

What treatments are available for pancreatic cancer?

While survival rates are low, some treatment options are available.

"Usually it's treated through some sort of chemotherapy and radiation," Fleshman said. "If it's detected early enough and hasn't spread, some patients are eligible for surgery."

To improve a patient's chances, PanCAN also recommends:

Clinical trials at diagnosis and during every treatment decision

at diagnosis and during every treatment decision Molecular profiling of the tumor to help you figure out the best treatment options

of the tumor to help you figure out the best treatment options Getting an opinion from a specialist, a physician who diagnoses and treats a high volume of pancreatic cancer patients

a physician who diagnoses and treats a high volume of pancreatic cancer patients Symptom management and supportive (palliative) care, provided early in the diagnosis as well as during and after treatment

When it comes to Trebek, CBS Boston's Dr. Mallika Marshall said that although the numbers around pancreatic cancer are grim, there's reason to be optimistic.

"You heard him. He's going to fight it, he's tough, he's got support and he's going at it whole hog," she said. "And people have beaten it. And they certainly have had longer survivals than even their doctors may have told them. And you do hear some rare cases of people who lived years with it. So let's give him a chance."