How one revolutionary test could change the health of millions.
If you’ve ever had a colon cancer screening or a mammogram — and sorry to nag, but if you’re a woman over 45, you should have had both by now — you know that they’re a bit of a pain. You have to make an appointment, go into the office, and deal with some inevitable discomfort and maybe even some prep work (assuming you’re getting a colonoscopy). Those screenings are both very important and very accurate, but they each only test for one type of cancer.
To date, only four cancers — breast, cervical, colorectal, and lung — have available screening methods that have been recommended by the United States Preventive Services Task Force. And even if there were screening methods for the more-than 100 known cancers, getting individually screened for each one would be a full-time job. But what if, in addition to the current recommended screenings, you could screen for many other cancers with a single blood test?
That’s what we can hope for from the next major breakthrough in cancer research: a multi-cancer early detection, or MCED test. Essentially, many cancers shed tiny fragments called biomarkers into the bloodstream; one common biomarker is called circulating tumor DNA (or ctDNA). MCED testing is able to detect patterns or changes to ctDNA and other biomarkers in a blood sample, allowing doctors to potentially catch the disease at its earliest — and most treatable — stage.
We spoke with Tomasz Beer, M.D. and Chief Medical Officer for Multi-Cancer Early Detection at Exact Sciences, about how MCED testing could help you take control over your future health, and what it means for the future of cancer care.
A blood test may catch cancer before symptoms emerge
It used to be that a cancer diagnosis was often a death sentence. While treatment has significantly evolved over the past few decades, there are still some cancers with disturbingly low survival rates. These “quiet killer” diseases, like pancreatic and ovarian cancer, are extremely aggressive but often don’t cause noticeable symptoms until they’re in the late stages, when treatment becomes much more difficult.
MCED testing could change this reality for people with these types of cancer. “Preliminary data suggest that this type of testing may be good at detecting very aggressive cancers like ovarian, pancreatic, esophageal, and liver cancer,” says Dr. Beer. “We hope to see a lot of impact on those cancers.”
Lung cancer patients will likely benefit most
Dr. Beer says he anticipates the most powerful impact of MCED testing to be seen in lung cancer patients. “Lung cancer is by far the number one cancer killer today, and the current screening test is a low-dose CT scan. But it’s only recommended for a subset of individuals — those with a 20 pack-a-year smoking history or more within the past 15 years — and less than 10 percent of eligible individuals are actually screened,” he explains.
For the thousands of people who develop lung cancer but don’t qualify for lung cancer CT screening — either because they never smoked or quit decades ago — MCED testing may lead to a diagnosis when early intervention is still possible, potentially saving countless lives.
Reduces the need for multiple, specialized cancer screenings
A rare cancer diagnosis can be particularly devastating. That’s because these diseases tend to get significantly less funding and have much smaller patient sample sizes to test from, so the likelihood of developing a dedicated screening method for them is very low.
Dr. Beer explains why MCED testing may have a major impact on patients of these lesser-known cancers: “I’ve had the opportunity to work with physicians who care for patients with gallbladder cancer. That’s one you don’t hear about very often, but when you get into the room with people fighting these cancers, you see what an uphill battle it is. When a cancer isn’t common, there’s little chance to develop a screening test, but when you add these rare cancers up, they’re actually an enormous health burden. MCED testing has the potential to detect multiple rare cancers, so that’s another area where we anticipate a big impact.”
You’ll have to keep doing your regular screenings
While all this news is exciting, don’t cancel your next mammogram just yet. “Our MCED test in development and other MCED tests out there are more sensitive for some cancers and less sensitive for others,” explains Dr. Beer. “This likely relates to how much DNA various types of cancer spill into the bloodstream. For example, breast cancer is less well-detected in our current version of the test, while lung, pancreatic, and ovarian cancer appear to be better detected.” The good news is that we already have a very reliable screening method for breast cancer (our old friend, the mammogram), so once MCED testing is more widely adopted, it could help complement these established screening methods.
Dr. Beer also notes that MCED testing does have some limitations compared to other screening methods. He explains that traditional colon cancer screening is more proactive than you might think: “Colorectal cancer screening isn’t just detecting cancer, it’s detecting pre-cancer. Those precancerous lesions that can be removed with colonoscopy prevent the development of colon cancer. We believe now that pre-cancer detection accounts for about 75 to 80 percent of the life years gained from colon cancer screening.”
Dr. Beer says he envisions a future where people will still be screened for breast cancer, colorectal cancer, cervical cancer, lung cancer, and possibly prostate cancer through traditional methods — and that “the addition of MCED testing may help detect much of the rest of the cancer burden.”
MCED could become a routine part of checkups…but not for a while
While the wide availability of MCED testing is the future we hope for, there’s still considerable work ahead needed to answer the remaining questions about these tests. “Our ultimate goal is to develop an FDA-approved test that would be widely available, included in guidelines, and reimbursed by Medicare and commercial insurance,” says Dr. Beer. “But that’s still years away.” In other words, we’ll need to be patient.
While many MCED tests are currently in development and one is currently available by prescription, the one Dr. Beer and the team at Exact Sciences are working on is currently in the study phase. “We’re running a study with two large health-system partners: Baylor Scott and White in Texas, and soon at Endeavor Health in Illinois,” explains Dr. Beer. The goal is to first test 10,000 participants and then expand that to up to 25,000 participants, testing them annually for three years and following up for several years after that. This study will provide valuable insight to further inform the development and commercialization of the company’s future MCED test and support discussions with regulatory agencies, payers, and guideline bodies.
There are still a number of other considerations the team at Exact Sciences will have to make before their MCED test becomes widely available: How does the test perform? When should people start getting tested, and how often? Should that recommendation change depending on family history or risk factors? “When it comes time to make these choices,” says Dr. Beer, “we’ll be guided by evidence to help us understand where the test can do the most good and the least harm at the same time.”
In a hoped-for future where MCED testing becomes routine, MCED tests may either be able to provide patients with more peace of mind, or give them the capability to act quickly when presented with a diagnosis. Either way, the potential implications are enormous: This could be a brand-new chapter in the fight against cancer.
