Can this new test compete with stool-based tests or colonoscopies? A radiation oncologist shares his opinion.
Key Points
- Colonoscopies remain the gold standard for detecting and preventing colorectal cancer, experts say.
- New blood tests like SimpleScreen CRC offer an option for those hesitant about colonoscopies.
- Early detection of colorectal cancer is key, as colon cancer is very treatable if caught early.
As many as 60 million American adults are overdue for their colonoscopy. “Nobody wants to talk about their bowels,” says Amar Rewari, MD, MBA, FASTRO, chief of radiation oncology at Luminis Health and adjunct assistant professor at Johns Hopkins School of Medicine.
But that reticence can lead to serious consequences. According to the National Cancer Institute, roughly 4% of us will be diagnosed with colorectal cancer in our lifetimes. And patients are getting younger and younger, says the American Cancer Society, with roughly one in five diagnoses coming before the age of 55.
If this sounds scary, it doesn’t have to. Rewari says that colorectal cancer can be “very treatable” if caught early. And last week, a company called Freenome announced that the FDA had approved SimpleScreen CRC, its blood-based colorectal cancer screening test for adults over 45 who are at average risk for the malady. It follows other tests, such as Guardant Health’s Shield blood test, which was approved in 2024, but improves upon them by using AI, says Rewari.
“It can look at some DNA fragments and some other patterns, methylation patterns, and other molecular features,” he explains. “It uses AI to take all those little weak signals and combine it together to see the risk of the person having cancer.”
But just because such tests exist doesn’t necessarily mean it’s what’s best for us. When asked if he will recommend SimpleScreen CRC to his patients, Rewari says it’s hard to say. “It’s an interesting and complicated question,” Rewari says. “The gold standard for screening for colon cancer is still a colonoscopy.”
The reason, he says, is that colonoscopies not only detect cancer but also polyps that can then be removed at the time of colonoscopy before they turn into cancer. It’s the same reason that he doesn’t recommend stool-based tests such as ColoGuard.
Still, Rewari says that there are circumstances in which it might make sense to try colonoscopy alternatives. “If somebody is really anxious about doing a colonoscopy, the other way to do screenings used to be to do stool-based blood tests. People would have to sample their own stools and dip it in to see if there’s blood on, and then send these readings to the lab. People don’t like to do that, obviously. So I think this test fills the gap,” he says. He would prefer that patients try a blood test over doing nothing at all, he says.
Rewari cautions patients, though, that if they are in any way high-risk for colorectal cancer, this test is not for them. “Let’s say you have some hereditary syndromes, prior history of cancer, you have inflammatory bowel disease or you’re symptomatic. Let’s say you have rectal bleeding,” he says. “Those patients should not get this test at all. They definitely have to do a colonoscopy. This really is meant for just routine colorectal cancer screening.”
The physician says that people who get regular colonoscopies—with a frequency of 10-year intervals for most healthy adults—have every reason to be optimistic. “It’s extremely treatable if it’s caught early or in a precancerous phase. And even if you did catch it when it is cancer, if it’s an early stage one, stage two cancer, cure rates are well above 80%,” he says.
While SimpleScreen CRC is an exciting addition to our options, there’s no replacement for a classic colonoscopy.