AceShowbiz - "The Crown" star Olivia Williams dished on her long arduous journey with pancreatic cancer, revealing she experienced years of misdiagnoses and dismissals by doctors. She now supports the upcoming TCS London Marathon's charity of the year, Pancreatic Cancer UK, calling for a cheap test that would lead to earlier detection of the disease.

In a revealing interview with The Times U.K., The Crown star detailed her battle with VIPoma (vasoactive intestinal peptide-secreting tumor), a rare neuroendocrine tumor of the pancreas that is detected in only 1 out of 1 million people annually. Pancreatic cancer is notoriously difficult to diagnose early, making it one of the deadliest common cancers.

Williams first encountered symptoms a decade ago, which marked the beginning of a four-year journey visiting ten different doctors in three countries to identify her illness.

She recounted being misdiagnosed with lupus, perimenopause, and other forms of cancer multiple times. It wasn't until a dedicated gastroenterologist in Los Angeles tested for a rare hormone and ordered a CT scan and biopsy that the correct diagnosis was made.

Reflecting on her experience, Williams expressed frustration at the delays in her diagnosis, "If someone had f***ing well diagnosed me in the four years I'd been saying I was ill, when they told me I was menopausal or had irritable bowel syndrome or [was] crazy - I used that word advisedly because one doctor referred me for a psychiatric assessment - then one operation possibly could have cleared the whole thing and I could describe myself as cancer-free, which I cannot now ever be."

Following her diagnosis, Williams has undergone numerous procedures to remove the tumor and portions of her pancreas, spleen, gallbladder, and liver.

Despite these efforts, the tumor had metastasized and continues to re-emerge, forcing her to undergo continuous treatment. This includes targeted internal radiotherapy involving radioactive material injections that require her to isolate from human contact for two weeks at a time.

Although these treatments have not eradicated the metastases, they have managed the cancer's progression to some extent. Williams admitted, "It's supposed to buy me maybe a year, maybe two or three years, of freedom from treatment. In the best-case scenario it would have made [the metastases] disappear but that didn't happen."

While it's "too late" for her to benefit from earlier detection, Williams urges those over 40 to stay vigilant about their health, emphasizing the need for simple, early tests, "This is where I get emotional but I'm not looking for sympathy, I'm looking for a cheap, early test."