Demystifying New Diagnostic Technology in Cancer Detection: Q&A With Alicia Zhou and Dr. Bill Dahut

The recent torrent of innovation in cancer screening technologies promise significant improvements in early detection and diagnosis. While many of these novel or non-standard techniques and approaches have the potential to improve patient experiences or screen for cancers that were previously unable to be screened for, some of the most promising are still being evaluated. So what is the right way to think about integrating these novel technologies into preventive care?

That’s a question that is top of mind for both employers and their employees. Dr. Alicia Zhou, Color’s Chief Science Officer, sat down recently with Dr. Bill Dahut, an oncologist and Chief Scientific Officer at the American Cancer Society (ACS) to better understand the current innovation landscape in cancer diagnostics as employers continue to plot out their benefit offerings.

In the first portion of what will be a two-part series on new diagnostic technologies, Dr. Zhou and Dr. Dahut discuss emerging tools in the field, including whole-body imaging and liquid biopsies, and how these new technologies may (or may not) transform cancer screening and early detection.

Dr. Zhou: In the past decade, we’ve seen many new screening technologies hit the scene. We may attribute this boom to declining costs, increasing availability of genetic sequencing, and general improvements in technology. What emerging trends in cancer screening are you most excited about?

Dr. Dahut: We’re certainly seeing increased attention on technologies and approaches that make it easier for folks to get screened—a trend that we’d love to see continue. A lot of our current screening approaches haven’t altered much over the past decades. Take a look at what we do for screening right now: mammography is a 50-year-old technology. Colonoscopies are the gold standard, but they’re very time intensive, expensive, and difficult to schedule. Lung CT scans are a bit more efficient today than they used to be, but still they can be hard to access.

Now, we have at-home stool-based testing to screen for colorectal cancer, and we’re even starting to use blood and urine to screen for different cancers and sometimes even multiple cancers at once.

There’s also a lot of excitement around being able to better determine who should be screened in a more focused way and finding ways to screen for cancers that we’re not actually screening for now. With these new tests, it’s important to make sure everyone is aware of the benefits of them and to understand who they’re not ideal for.

Dr. Zhou: It will be interesting to see how new technologies improve access to cancer screening. You mentioned some of the emerging technologies that enable multi-cancer early detection. One that’s top of mind for me is whole-body imaging—MRIs or CT scans—which aim to detect as many solid tumors as possible. But in healthy individuals, this can feel like casting a very wide net. What do you think of using whole-body imaging as a way to detect cancer early?

Dr. Dahut: Whole-body imaging has its pros and cons. You would find more cancers, yes. But, you also run the risk of false positives, which can lead to unnecessary follow-up or anxiety for patients. They might spend months being evaluated for something that was never a cancer. 

Full-body imaging studies, by and large, are also expensive. They heighten radiation risk, and they’re subject to interpretation of the person reading them. Additionally, we’re missing data that proves whole-body imaging actually improves cancer outcomes or reduces costs. Of course, anecdotally, there’s always a story about somebody who has a full body MRI and finds cancer. 

Dr. Zhou: Another interesting area of innovation in diagnostics is liquid biopsy. Today, these blood-based tests are often used to look for specific molecular markers of cancer to guide treatment and to detect minimal residual disease after treatment. But now, liquid biopsies are starting to be used for screening. Where do you see liquid biopsy playing a role in the future of cancer screening? 

Dr. Dahut: Traditionally, for a cancer patient, biopsies were used to establish an initial diagnosis. But in the last 25 years, we’ve learned that cancers can change over time—particularly after one’s started treatment—and that depending on where you biopsy the tumor, you may get a different result. The Holy Grail for the past decade or so has been to capture the molecular signal for a tumor with a simple blood test—a liquid biopsy. 

For screening, certainly, blood-based tests are much more attractive for patients. They’re easier to schedule and don’t carry a radiation risk. The difficulty is finding the population for which blood-based tests make the most sense and understanding how those interact with other screening tests. We’re waiting on blood-based testing data from the UK and are hopeful that we’ll see enough information to make recommendations about when to use these tests for high-risk groups.

In the scientific and medical communities, we hear a lot about false positives from these tests, which we have to consider when thinking about how to implement them on a population level. At the moment, these blood tests can be a useful way to determine who should have another test. But they shouldn’t be used in place of the gold standard screenings. 

Dr. Zhou: The ACS has done a great job of keeping up with new technologies. How do you evaluate and incorporate these new technologies into screening guidelines?

Dr. Dahut: The process has changed. At ACS, guidelines used to be updated every 10 years or so, whether the changes needed to be made or not. We’ve now moved to what we call a “living guideline.” As we see new scientific evidence evolving, we can evaluate whether or not a guideline change should be made.

We have a team at the ACS Center for Cancer Screening led by Dr. Robert Smith, who’s internationally known for his cancer screening work. The process starts with a very intensive literature review. Then we bring together a large panel of external experts in cancer screening who comb through the details of the current literature and look at the science and the impact on patients to see whether or not there’s anything else that’s equivalent in the space. If there’s a similar technology that has already been approved, that’s much easier to adopt. We also look at what other guidelines are out there from task forces and professional societies. And then ultimately, based on that work, we move forward with guideline changes in a peer-reviewed fashion.

This process helps us change guidelines in a much more fluid way. It’s not as quick as people would like it to be, but it’s effective.

Dr. Zhou: While these technologies are still being evaluated, what role should they play in patient care? Should they only be used in research, rolled out to a small group of early adopters, etc.?

Dr. Dahut: Safety is always the first step to approval for a new test or device. In the time between a new screening technology coming to market and making it into a national guideline, we need to see evidence of its safety, practicality, and outcomes in healthy populations – whether it’s real-world data or data from a clinical trial.

Overall, we would love to see new technology or new applications of existing technologies make cancer screening as easy as possible. While colonoscopies remain the gold standard for colorectal cancer screening, FIT and FIT-DNA (Cologuard) tests can help to remove the barriers associated with arranging and receiving a colonoscopy. While there may be skeptics of these new technologies, others believe that some effective screening is better than nothing. Of course, we need rigorous data to understand the benefits of new tests and who they may or may not be a fit for.    

Stay tuned for Part II of this discussion, which focuses on how employers and organizations should think about making these kinds of screening technologies available at a population scale.