Pancreatic cancer, which felled “Queen of Soul” Aretha Franklin on Thursday is tough to spot in its early phases, and nearly always overwhelming in later stages, making it one of the deadliest cancers in the U.S.

Pancreatic cancer has claimed the lives of other notables, including Apple founder Steve Jobs, actor Patrick Swayze and Italian operatic tenor Luciano Pavarotti.

According to a family statement, Franklin, 76,  died of a rare type of pancreatic cancer “of the neuroendocrine type,” USA Today reported. It accounts for only 6 percent of pancreatic tumors and is fatal.

When Franklin was formally diagnosed with the cancer was unclear, but her waning health could be seen as far back as 2010 when she was diagnosed with an “unspecified illness” widely reported as cancer, The Sun said.

Franklin dismissed the claims and continued to fend off persistent rumors she had pancreatic cancer over the years, People magazine reported.

Earlier this week, reports emerged that Franklin was “gravely ill” and under hospice care, and that her family had gathered to be with her. She succumbed to the cancer within days.

According to Scientific American, the incidence of pancreatic cancer in the U.S. alone has been rising steadily by 0.5 percent each year for the last decade.

The American Cancer Society estimates that in 2018 about 55,440 people will be diagnosed with pancreatic cancer and about 44,330 people will die from it.

What makes pancreatic cancer such a difficult illness is that it is notoriously difficult to spot and to diagnose, Prevention magazine reported.

Neil Woody, an oncologist at the Cleveland Clinic, explained this was partly because it has been difficult to establish good screenings for the general population.

“Tests with high likelihood of detecting pancreatic cancer, such as endoscopic ultrasound, are invasive, costly, and may carry risks of complications that outweigh their use as screening tests for the average person,” he said.

It doesn’t help that many people don’t show any symptoms until the cancer has spread to other organs.

“What makes it so challenging is there is no early detection,” said Julie Fleshman, president and CEO of the Pancreatic Cancer Action Network (PanCAN), an advocacy organization, according to USA Today. “Usually by the time it is diagnosed it is late stage and more difficult to treat.”