Alex Trebek ended his announcement Wednesday that he has Stage 4 pancreatic cancer with a somber vow.

“I’m going to fight this,” said the beloved “Jeopardy!” game show host. “I plan to beat the low survival-rate statistics for this disease.”

But exactly how hard is it to beat pancreatic cancer? The answer: very. Pancreatic cancer has the highest mortality rate of all major cancers.

The National Cancer Institute tracked patients’ survival rates from the time of diagnosis and found that by the five-year mark, only 9 percent of pancreatic cancer patients remained alive.

In 2016, the disease became the third-leading cause of cancer-related deaths in the United States, overtaking breast cancer, and it is expected to overtake colorectal cancer to become the second-leading cause of cancer-related deaths in the country by 2020, according to the Pancreatic Cancer Action Network. (The leading cause remains lung cancer.)

What makes pancreatic cancer particularly deadly and difficult to treat is that the disease is often diagnosed too late. Tumors in the pancreas often don’t exhibit major symptoms until the cancer has already reached advanced stages.

“With breast cancer, you feel a lump. With colon cancer you see bleeding in stool. But when it comes to pancreatic cancer, there’s nothing like that,” Daniel M. Labow, chief of the surgical oncology division at Mount Sinai Hospital. He said that in his experience, unfortunately, only 50 percent of stage 4 patients make it to the one-year mark after diagnosis.

Most patients aren’t diagnosed until the cancer is at stage 3 or 4, when it is often considered inoperable and the only remaining option is chemotherapy.

“The primary way to deal with most cancers is to cut them out," said Valerie Lee, an oncologist at Johns Hopkins Sidney Kimmel Comprehensive Cancer Center. ”But with pancreatic cancer, only 10 to 20 percent of patients are even eligible for surgery. That leaves chemotherapy, which is not curative. It mainly extends the time you have left."

Pancreatic cancer almost always afflicts patients after age 45, with 71 being the average age of diagnosis (Trebek is 78.). One of the earliest symptoms is pain in the back or stomach. Other symptoms are jaundice and sudden, unexplained weight loss.

The pancreas sits toward the back of the abdomen, horizontally across the body. It secretes enzymes that help digest food and hormones that help regulate the body’s blood sugar. Like any cancer, pancreatic cancer occurs when cells in the organ start to grow and spread uncontrollably.

While doctors and researchers have made tremendous progress with other forms of cancers, pancreatic cancer has remained one of the few for which survival has not improved substantially over the past four decades. Over nearly a quarter-century, the overall cancer mortality rate has fallen 26 percent, resulting in almost 2.4 million fewer deaths than if peak rates had continued. Last year, a new report by the American Cancer Society showed the overall cancer death rate had declined again by 1.7 percent.

Increased funding, research and advocacy have helped. Widespread screening tests like mammograms and colonoscopies have allowed many to catch certain forms of cancer earlier. Unfortunately, there is no such safe and effective test for pancreatic cancer. And its related deaths have remained steady. In 2019, more than 56,000 Americans are expected to get the diagnosis, according to the American Cancer Society, and more than 45,000 will die of it.

Other notable figures who have had pancreatic cancer include opera singer Luciano Pavarotti and actor Patrick Swayze. Soul singer Aretha Franklin and Apple founder Steve Jobs had a rare type of pancreatic cancer, called neuroendocrine cancer, which progresses more slowly than the more common type.

Justice Ruth Bader Ginsburg was treated for colorectal cancer in 1999, and 10 years later doctors discovered pancreatic cancer at a very early stage in her body. It is not known which kind of pancreatic cancer Ginsburg had — the more common and typically more lethal kind or the neuroendocrine type. Ginsburg, 85, recently had surgery for two malignant nodules in her left lung.

Having public figures like Trebek speak out about their own experiences raises awareness and potential for much-needed funding and research on pancreatic cancer, said Labow, and it also helps others feel like they’re not alone.

“It’s a particularly hard diagnosis to receive. It can be a devastating and surreal experience,” he said. “To see how Alex Trebek is handling it — coming out publicly and owning it in a way and saying he’s going to try his best against it. You have to respect that."