It’s a dreaded diagnosis: Stage 4 pancreatic cancer.

Jeopardy! host Alex Trebek died Sunday from a disease that afflicts more than 56,000 Americans a year—most of whom will also die from it.

Although pancreatic cancer represents just 3 percent of all cancers in the United States, it is uncommonly lethal, accounting for 7 percent of all cancer deaths, according to the American Cancer Society.

That’s in part because it’s rarely detected early, when the chances of successful treatment and survival would be higher.

The pancreas, the fish-shaped organ that secretes insulin, is deep inside the body, so a tumor often remains hidden until the malignant cells have spread to other parts of the body, causing symptoms.

When the cancer is still confined to the pancreas, surgery is a treatment option. But once it has spread, chemotherapy is the go-to—as a way to extend life, not cure the disease. Target therapies and immunotherapies are considered the most promising avenues of treatment as researchers race to find new methods for early detection, including genetic tests to identify those most at risk and screening ultrasounds for those with a family history.

“Chemotherapy is really the standard of how we treat pancreatic cancer. But we have seen advances in how we molecularly and genetically approach the disease,” said Victoria Manax, chief medical officer for the Pancreatic Cancer Action Network, referring to targeted treatments that have led to breakthroughs in breast cancer and other kinds of cancer.

“Historically, targeted therapies have failed with pancreatic cancer but now we are starting to see different subsets of pancreatic cancer where there’s promise. It’s still a small percentage,” she said, adding that even the failures expand researchers’ understanding of the disease.

“This year our treatment guidance is that molecular profiles be done for all patients for pancreatic cancer.”

Fewer than 10 percent of pancreatic cancer patients survive for five years. But for stage 4 patients, that drops to 3 percent. And late-stage tumors can be vicious, killing within a matter of months.

There are, of course, patients who buck the odds. And Trebek hopes to be one of them. “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 announcing his illness.

Trebek lived 20 months after being diagnosed. He responded well to an initial round of chemotherapy but it came roaring back and he eventually switched to an experimental immunotherapy treatment.

Other well-known figures who have succumbed to pancreatic cancer include Patrick Swayze, who lived 18 months after his stage 4 diagnosis, and Apple founder Steve Jobs, who had a less-common and less-deadly form of the disease and lived eight years, undergoing surgery and a liver transplant during that time.

The late Supreme Court Justice Ruth Bader Ginsburg also had pancreatic cancer, but it was caught very early, by accident during a CT scan. A single tiny lesion was removed with surgery in 2009, but it returned this summer as Stage 4 disease and she ultimately died.

Americans have a lifetime risk of between 1 in 63 and 1 in 64 for developing pancreatic cancer.

Major risk factors include smoking and obesity. The risk also goes up with age. The average age of diagnosis is 71; Trebek was 78. Men are a little more likely than women to develop it, and African-Americans are at slightly higher risk. A family history of pancreatic cancer, and a history of diabetes or cirrhosis of the liver are also associated with higher risk.