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Researchers unveil new blood test that detects colon cancer

March 25, 2024

Elise Takahama | (TNS) The Seattle Times

Researchers at the Fred Hutchinson Cancer Center have unveiled a new type of blood test used to detect colorectal cancer, with high hopes not only in its ability to reduce barriers to testing for this particular disease, but also potentially pave the way for many other types of cancer screenings.

The study, published last week in the New England Journal of Medicine, analyzed results from nearly 8,000 people throughout the country between ages 45 and 84 and compared results of their blood tests to those of a colonoscopy. In all, the new test accurately detected colorectal cancer 83% of the time, which is “at least equal and maybe better than” a commonly used stool-based detection test, said Dr. William Grady, medical director of Fred Hutch’s gastrointestinal cancer prevention program and who led the study.

“We have a lot of people who are dying from a preventable cancer,” Grady said. “And the reason is they’re not doing colon cancer screenings. This is a real opportunity to improve that and prevent those deaths. That’s why I get excited about it.”

Colorectal cancer is the third-most diagnosed cancer and second-leading cause of cancer-related deaths among adults in the U.S., according to the paper. About 53,000 people are expected to die from the disease this year. Colorectal cancer is also increasingly being detected in younger people, with 20% of 2019 diagnoses in patients under 55 — almost double the rate reported in 1995, according to the American Cancer Society.

The trend prompted the U.S. Preventive Services Task Force, which regulates and makes recommendations when to complete certain screenings, in 2021 to lower the age to begin colon cancer testing to 45, five years earlier than previously recommended.

While researchers are still trying to understand what’s driving the change, higher obesity rates, more sedentary lifestyles and diets that include more processed foods are likely contributors, Grady said.

But early detection can significantly increase survival rates — jumping from 14% among those with metastatic cancer to a five-year survival rate of about 91% among those diagnosed at early stages, according to the Guardant Health-funded study. Still, just 59% of those eligible for screenings get tested.

“I think this is an enormous breakthrough,” said Dr. Rachel Issaka, a Fred Hutch gastroenterologist and colorectal cancer researcher who co-authored the paper. “We have another tool in our arsenal that allows people to have a noninvasive and easy way to potentially complete colon cancer screening.”

She noted the new test does not replace the colonoscopy, which identifies and removes precancerous lesions, and remains the “gold standard” for colon cancer screenings and prevention. But because the more involved procedure isn’t always easily accessible to everyone, especially communities of color and lower-income populations, Issaka is optimistic the new option can help boost screening rates and, ultimately, lower deaths.

Because blood tests are generally more convenient, relatively painless and have minimal risk involved, cancer researchers, including Grady, have considered it for decades as a tool in cancer detection, he said. Testing and analysis techniques, however, weren’t ever sophisticated enough to make it a realistic option, Grady said.

Then two “really big breakthroughs” came along, he said.

The first had to do with scientists’ ability to extract tumor cells’ DNA from the blood and process it, which has been developed and optimized over the last decade.

The second milestone involved “next-generation sequencing,” or analyzing DNA in ways that were sensitive enough to detect the rare tumor DNA present in the blood, Grady said. This sequencing has “rapidly advanced over the last 20-plus years,” including in ways to identify potential biomarkers, he added.

Next-generation sequencing hasn’t yet been widely used in cancer detection tests, but Grady’s excitement about the possibilities was evident.

“I think this [colon cancer] test is going to usher in a wave of other types of screening tests,” he said, pointing to ongoing clinical trials that screen people at risk for lung cancer and research around breast cancer blood tests. “Could you replace mammograms with this? I’m going to guess those types of studies will be coming out in the next few years.”

Despite enthusiasm around new technologies — including artificial intelligence’s role in more efficient data analysis — Issaka stressed an importance to pay attention to how these and future tests are rolled out in clinical spaces. It’s always the hope these interventions improve disparities, she said, but “it could also have unintended consequences of widening disparities if we’re not careful.”

Issaka’s lab at Fred Hutch keeps this mission at the heart of its work, specifically focusing on identifying and introducing solutions that reduce racial and ethnic disparities and improve colorectal cancer outcomes. Black and Indigenous communities, for example, report disproportionately high rates of colon cancer diagnosis and deaths, in part because of inadequate screenings, Issaka said.

“If people have more options that are convenient for them, they are more likely to participate in colon cancer screening, and we can pick up earlier cases where treatments are most effective,” she said.

In the past several years, her team has explored a number of strategies, including a program that mails stool-based tests (also known as Fecal Immunochemical Tests, or FIT) to 15,000 to 20,000 Seattle-area homes per year. The program identifies people eligible for colon cancer screenings, and checks in with patients to ensure they’re completing the tests. If someone has an abnormal result, the team works with them to schedule a follow-up colonoscopy.

Because transportation has also been identified as a common barrier to receiving a colonoscopy, Issaka’s team partnered with a service to coordinate rides for patients to and from their procedure.

At a recent community screening and educational event in the Central District, feedback from nearly 150 attendees was “overwhelmingly positive” in learning about the disease and how to find resources, Issaka said. The annual workshop, this year partnered with the First African Methodist Episcopal Church, provided information on what symptoms are, ways to reduce risk and how to get up-to-date with screenings, she added.

“Our goal is to bring as much awareness about this disease to these communities as possible,” Issaka said.

The blood test is still awaiting approval from the Food and Drug Administration and the Centers for Medicare & Medicaid Services, but Grady expects it should receive the endorsements this year.

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Orange County Register

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Researchers unveil new blood test that detects colon cancer

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