Healthcare Unfiltered
Healthcare Unfiltered is an honest, raw, timely podcast tackling any and all topics in healthcare that affect stakeholders. Dr. Chadi Nabhan uses his dynamic conversational skills to challenge his guests to address controversial and important topics. He also brings on world renowned experts to discuss clinical advances in medicine.
Healthcare Unfiltered
Episode 278: What’s New in Multicancer Early Detection With Tom Beer
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Returning guest Dr. Tom Beer, Chief Medical Officer for Multicancer Early Detection (MCED) at Exact Sciences, joins the show to break down the promise and complexity of MCED testing—what it is, the clinical gap it aims to fill, and how it could reshape cancer diagnostics. He explores which patient populations may benefit most, the current limitations across different cancer types, and whether MCED tests are poised to complement or replace traditional single-cancer screening approaches. The conversation also tackles key nuances like balancing sensitivity and specificity, interpreting negative results, and how clinicians and patients should think about repeat testing in an evolving screening landscape.
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It's Healthcare Unfiltered, and it's your host, Shadi Nabhan. I'm a hematologist and a medical oncologist with interest in all aspects of healthcare delivery, treatment, leadership, mentorship, and policy. Folks, thank you so much for tuning in. We are in year number six, season number six of Healthcare Unfiltered. I couldn't have made it here without your support, without listening, without providing your candid advice and suggestions to this podcast. So thank you. Today's podcast was with Dr. Tom Beer, a GU medical oncologist, who is the chief medical officer at Exact Sciences responsible for developing multi-cancer early detection test. Multicancer early detection, or MSAT, essentially what we are doing is we're trying to detect cancer before where otherwise we couldn't have detected them. In other words, if you do a blood test and the blood test tells you that there is a possibility of cancer here because you found DNA or you found evidence of cancer on the molecular level, then you do an imaging study and you find where that cancer is and you can intervene. Now, sometimes you may do an imaging study despite the fact that the MSAT test is positive and you don't find anything, but that we call that false positive test. I've had Tom on the show over a year ago when we talked about the Falcon study, the Falcon study that is screening a large number of people to try to identify the benefit and the value and potentially the frequency of when you are doing the screening test, the MCT, which is called Cancer Guarded Exact Sciences. So I've asked him to come back on the show today to talk about what have we learned so far over the past year and a half, what is new in multi-cancer early detection, what are the positives, what are the negatives, lessons learned, and really what is the path forward. I admit that one of the concerns I personally have that when we think about screening, I just don't think we should screen the entire uh people. We can't really screen everybody, and we really have to define what is the what is the population that should be screened. And in my view, maybe that population should be the population at risk of developing a particular cancer. Is it, for example, smokers? Is it X, Y, and Z? And uh so that's really the concern in general when you do MSAD or multi-cancerly detection on everybody. Uh obviously the attraction of that is that if you screen everyone, um that um that is that could be pretty lucrative from a marketing perspective, but I think we have to start, we have to try to understand who needs screening and who doesn't. And Dr. Beer is extremely thoughtful, he's very methodical, amazing researcher and a clinician. He's seeing patients in clinic with prostate cancer uh as he continues his role at exact sciences, and he's going to really help us dissect all of this information and try to understand it and and and really draw the path forward for all of you. So thank you, Tom, for everything you're doing. Thank you for coming on my show for the second time. And I appreciate uh you explaining to us what's happening with the MSAT multi-cancer early detection. And folks, before I air the episode, please check out my website, shadynabhan.com. Check out my books, Toxic Exposure and the Cancer Journey. Stay tuned for two more books in 2026, one on AI and cancer care, and the second one is my first fiction. It's a medical thriller. It is the first fiction coming out in late 2026. So stay tuned for that. And without further ado, Dr. Tom Beer on Healthcare Unfiltered. Well, he's back, Dr. Tom Beer. I I thought you'd learn your lesson. Welcome back to my Healthcare Unfiltered podcast.
SPEAKER_00I'm glad I convinced you to come back. I love it. Love love being with you here, Chadi. Very good to uh visit again. I gotta send you another t-shirt now, I think. That sounds great. I love the first one.
SPEAKER_01Yeah. Um, so Tom, just really quick intro, just for folks who uh may have surprisingly missed the first episode we did, which is goodness, it's probably 14 months now uh ago that we've done this. Uh just about you and uh and what you're doing.
SPEAKER_00Sure. So first and foremost, I'm a medical oncologist and um I see patients with prostate cancer about half a day a week still. Over the last three and a half years, I've moved over from a full-time academic practice to serving as chief medical officer for multi-cancer early detection at Exact Sciences Corporation, where I've been working to develop uh what's now become CancerGuard, uh, our multi-cancer early detection test.
SPEAKER_01So just basics. What what is multi-cancer early detection test, like for a general oncologist or even for for a primary care doctor?
SPEAKER_00Sure. So let's let's just start with the problem that we're seeking to solve. Uh you know, today we routinely screen for only a handful of cancers. And about 70% of cancer diagnoses and cancer deaths occur due to cancers that we don't screen for, and so we often don't detect them early. And I I think, you know, as we work our way through the challenges in this field and develop better tests, there will come a day when we'll look back on this reality the way we look back on the days of um no cell phones or or or even no internet. You know, it's sort of unbelievable that more than two-thirds of cancers are are are just um come as they will and we don't look for them. So that's the problem we're trying to solve with multi-cancer early detection. What it is is uh a blood-based test that is uh measuring markers from many different cancers in a blood sample, and it seeks to um give us an early warning of many different types of cancer and complement the routine standard of care screenings like um colon cancer screening, breast cancer screening, cervical cancer screening of today.
SPEAKER_01So you say complement your this is not to replace your thinking?
SPEAKER_00Yeah. You know, blood is a wonderful medium because it integrates the s uh signals from the entire body. You know, if you think about it, blood's everywhere. And so it is the best place to look when you're trying to assess uh many different cancers at the same time. However, uh because blood is not um a direct reflection of the organ of interest, our ability to pick cancers up in the blood is not as good uh as it is with a more focused test. We see that, for example, in colorectal cancer screening, where we now have colonoscopy, stool-based tests like Colagard and FIT, and uh recently the development of some blood-based tests. And we see in those blood-based tests that the sensitivity for early cancer and certainly for pre-cancer is much lower than stool-based tests. And so we think blood is not going to get to a place where it can replace um colonoscopy or coligard mammography, pap smears, uh, or or lung cancer screening. But there are so many other cancers that we don't look for at all. And some people miss their standard of care screenings, and that's where uh a multi-cancer early detection test can uh fill the gap.
SPEAKER_01So when we talk about multi-cancer early detection test or MCD, are we asking of the test to detect any possible cancer known to man? Are we talking about sarcoma, melanoma, pancreas cancer, GBM, lymphoma, myeloma, like uh because there's like gazillion cancers out there. So what are what are we asking of an MSAT test to do to detect what?
SPEAKER_00Yeah, so you know the limits of detection of these tests across cancer types are um uh hard to define because there are so many cancer types that uh uh you'd have to get samples from patients uh with very rare, uncommon cancers and so on and so forth. I mean, with with uh the exact sciences test called CancerGuard, we we looked at um more than 50 cancer types and subtypes, and um uh it's a really broad range that represents well over 80 percent of the whole cancer risk. But it's pretty likely that it would detect more. We just haven't looked at it yet, um, and we will learn that as we continue to go. We also know that the the level of um sensitivity or ability to detect a cancer isn't the same for all cancers. There are some that secrete a lot more signal into the bloodstream. They tend to be the more aggressive cancers like lung, ovarian, um uh pancreatic, esophageal, gastric, and others that are tougher to detect. So I think it's a broad range. It's probably not going to be every single cancer, um, but it's not equally effective for each cancer. So we're a lot more to learn on that.
SPEAKER_01And is the reason, like what's the reason some cancers are not detected? Is that the same reason when we talk about tumors shedding and things of that nature? Or is it like too early?
SPEAKER_00Yeah, so our test uh is a multi-biomarker class test that includes DNA methylation and proteins. And you know, that those two we believe are complementary, and so they go beyond a single biomarker class. But not every cancer type secretes cancer-associated proteins in the bloodstream. And DNA shedding varies by cancer type. Um so, yeah, absolutely. Just the shedding, the level of shedding um varies from cancer to cancer. It's lower at earlier stages, and so that's why um these tests are variable in their sensitivity, and that's why they're not likely to replace dedicated uh proven single cancer screening tests. The primary goal is really to expand the reach of screening to many more cancer types.
SPEAKER_01Like any screening test, the um you know the the holy grail is to find that sweet spot between sensitivity and specificity. I mean, I can't, you and I know how many articles have been written about pitfalls of screening tests, whether it's mammogram, PSA, and so on. It's always hinders on that balance of sensitivity and specificity. If we all concede that there is no perfect test out there, no matter what, what's a realistic thing that you would like to see sensitivity and specificity, and what are you seeing with the cancer guard?
SPEAKER_00Yeah, so let's first uh talk about the single cancer test. So just for the audience, you know, specificity is a is a measure of how likely are you to get a false positive result. Um in other words, a positive test that doesn't that that ultimately does not lead to a cancer diagnosis. And our commonly accepted tests um range from about six percent for coligard to um twelve or thirteen percent for pneumography and so forth. And you know, let's just say between six and ten percent just to be just to be safe. So that's quite a high number. And if you think about uh an individual who um gets screened for multiple cancers over time, a false positive is pretty common with routine screening. We accept that in exchange for cancer early detection. And we also accept it because we're we're kind of accustomed to it, we know what to do, the workup is straightforward. You know, you get a positive stool-based test, you do a colonoscopy, everybody understands that, and and folks aren't afraid of that. Uh with um multi-cancer early detection tests, we're we're seeking a higher level of specificity so that false positives are less common. The current version of CancerGuard, what we reported out of our case control study was a specificity of 97.4 percent. Because of some limitations of that study, uh we think that might end up being a bit higher in the real world. So um yeah, I'm I'm not at liberty to kind of cite a different number until we do the work. But uh, you know, we're we're looking at one or two percent of individuals um encountering a false positive, which is much, much lower than what we are accustomed to with single cancer screening tests. That's also well justified because you know the diagnostic workup for a multi-cancer early detection test is uh is a bit more complex.
SPEAKER_01We uh when you do the test, um we're taking uh blood sample.
SPEAKER_00Yeah.
SPEAKER_01And uh we're looking at uh basically DNA fragments from tumor cells that probably are undetected uh radiographically, right?
SPEAKER_00Um you know what we find is that when the test is positive, um typically imaging does show a cancer. So I'm not sure that they're undetectable radiographically, but it would be impractical to scan 100% of the population with high-resolution imaging. So it's a solution to make that detection much more efficient. You're you're ending up working up one or two percent of people instead of a hundred percent of people.
SPEAKER_01Yeah, I guess what what I what I was thinking, maybe I was thinking out loud that there are some patients that uh I think it goes back to your point of the false positivity. There are some patients where you would see the positive test and you do imaging and you don't find anything, but the majority you will find something.
SPEAKER_00Yeah. Um Yeah, I mean, we we looked at that question, Chadi, and and so we had in in Detect Day the original study that looked at a uh earlier version of our test. There were 98 such patients out of 10,000 participants, so um uh just under 10 per 1% rate. Um and you know, we talk about those folks a lot, but I just want to come back to the idea that 99% of individuals in that study did not have a false positive. They largely got a reassuring uh report. Um but of those 98 individuals, we have four and a half years of follow-up. There were three cancer diagnoses over that period of time. Uh and uh it's we can't prove that they were new cancers that weren't missed by the test. But um the the risk of cancer in that population is about one percent per year, and we saw under one percent per year. So we we feel that that our approach to a diagnostic resolution when it when it delivers a reassuring result, um the risk appears to be uh back to baseline.
SPEAKER_01I'm gonna I'm gonna suggest that the most important question uh in any screening test, whether it's mammogram, PSA, colonoscopy, or blood-based assay, is the patient population we're screening for.
SPEAKER_00Yeah.
SPEAKER_01Um what do we know there? Like, you know, in in terms of what is who are the patients that you think today, or maybe that you would include in doing an MSAT testing? Because like you said earlier, you're not gonna screen the entire population, obviously.
SPEAKER_00Yeah. Well, um, so what I was referring to earlier is that you wouldn't image an entire population with with imaging as a screening test. Sure. You know, for for our test, um we've developed uh um uh an uh indication for use for individuals 50 to 84 based on what we know about their pre-existing cancer risk. And modeling screening in that population, um we see um the potential for a substantial reduction in metastatic disease burden and a substantial reduction in cancer mortality. So that's where we're aiming the test is 50 to 84. Of course, age is a risk factor for cancer, so that is a way of risk stratifying individuals. Now, people might uh initially, as this these technologies emerge, focus on um individuals with additional risk factors, obesity, heavy alcohol use, smoking history, family history, and that's certainly a reasonable approach as well. So I think there are some uh narrow more narrowly defined populations, but we didn't want to limit the test so that um folks at at average risk, but at an age where cancer becomes a significant issue uh couldn't take advantage of it. You know, we it's worth remembering that one in two men and one in three women face a cancer diagnosis in their lifetime. So while we can uh you know look at individual cancers and short time intervals and point to relatively low risk, over that period of time from 50 to 84, the probability of cancer is quite significant.
SPEAKER_01So so the patient population we are looking to, the people, I don't say patient because they're not patients, right? People we are screening for is anybody over the age of 50.
SPEAKER_00Yeah.
SPEAKER_01Um, regardless of other risk factors per se.
SPEAKER_00Like, yes, that's that's who we're offering the test to, also at the discretion of a prescribing healthcare provider. Yeah, if they determine that um somebody who's under 50 but has significant risk factors uh would benefit from the test, we're not gonna prevent them from making that recommendation. We'll we'll run those tests as well. But what we we've designed our sort of intended use statement, which defines how we see uh the test playing a role in public health as people 50 to 84.
SPEAKER_01Now, when the test is positive, obviously we all know what to do. You're gonna image, you're gonna try to find um the cancer and so on. But when it's negative, do we have any data into how frequently you need to repeat it? What do you do in the negative in the situation where it's a negative test?
SPEAKER_00Well, a couple things there. First of all, um maybe I'm sounding like a broken record on this, but uh folks need to stay on top of their recommended screening tests. So uh a negative MCED test is not a guarantee of cancer-free status. And if they're due for colorectal cancer screening, mammography, cervical cancer screening, if they decide on the PSA test, if they're a smoker and need lung cancer screening, they need to keep up with that. It's it's not a hall pass uh out of that. Secondly, um at this point, we're thinking about recommending an annual interval. We are doing a study that is uh it's called Falcon, where up to 25,000 individuals are being tested, and we're doing three annual tests, so we're gonna learn uh about how that interval works. But if you think about how do you design the interval for screening, it really comes down to early stage sensitivity and in some cases pre-cancer sensitivity. You know, if if you can detect um like stool-based tests like COLIGARD, 95% of early stage colorectal cancer and about 40 percent plus of pre cancer, then a three-year interval is appropriate because it's unlikely that um uh things would change that quickly, you know, if you if you've screened for those cancers. As we mentioned, the blood-based cancer uh screening tests are not quite as sensitive. And so, you know, we have a combined stage one and two sensitivity of about 39 and a half percent across a broad range of cancer types. That's very good given that we don't screen for most of those cancers, and so sensitivity is zero. But it's not good enough to take a negative test and say, oh, I'm free and clear for two or three years. So we're thinking annual at this point.
SPEAKER_01Annual, like not just for three years.
SPEAKER_00Uh gosh, you know, these technologies are so new that we've not looked at them beyond. Yeah, because you said like Falcon.
SPEAKER_01I when I had you on the show last time, we talked about Falcon. I was very impressed by the trial. I was very intrigued by it. Yeah. This was a large-scale study looking. Trying to answer a question that is very important, and you were doing this in the context of a clinical trial, which I I congratulate you on. Thank you. That that I mean I may have missed it, but nothing has been published from that trial, right? Yeah, okay, good. So I didn't miss it.
SPEAKER_00No, it's still ongoing.
SPEAKER_01But in that trial, you were doing it yearly for three years. Yes.
SPEAKER_00Yeah, I mean, that's just uh, you know, Charlie, that's the design of the study. We we can't uh practically speaking continu. I mean, it'd be lovely to continue longer, but there there are realities and practicalities of um resources and and just the need to get to the data. But we know that um that cancer risk that over a lifetime is one in two for men and one in three in women is divided into sort of one to one and a half percent per year, depending on your age and your risk factors. And so um I would think that if the tests uh uh you know prove effective over a three-year period, then long-term annual testing would be appropriate. But that is uh, boy, that that is a question for for future experience and studies.
SPEAKER_01So the the uh I mean, yeah, any trial you need to have limitations. I mean, it's just the way it is. So you chose arbitrary three years, but uh you could make an argument that some people might want to, in real life, they may want to do it more than just for three years.
SPEAKER_00Yeah, no, I think I think that right now we're we're recommending annual between ages of 50 to 84. You know, these are so imagine in the Falcon study we're gonna do the test three times, and then we're gonna follow patients for a total of seven years. So we will see. I mean, for example, what if having three negative cancer guard tests uh gives you uh a very low risk of cancer over the ensuing two or three years? Maybe if we learn that, we'll we'll come back, share those data, and and that recommendation for annual testing might stretch out to well, if you have several negative tests, you could go every other year. I'm just kind of hypothesizing here. But our our current view until we learn more based on what we know about cancer epidemiology and test performance is annual testing.
SPEAKER_01I have to tell you the thing that scares me the most, and that's just me, and and you'll have to help me maybe overcome that, is that although you put like guardrails into we think folks over the age of 50 until A4 should undergo annual, let's say. Yeah. You know, there's nothing that's gonna prevent a physician of ordering that test on a 32-year-old healthy person because that 32-year-old healthy person really wanted to know. And I worry about what that means because then a lot of it's like almost everybody undergoing colonoscopy at the age of 30. It's just easier because it's a blood test, right? So so do you fear that um that people when if it's available, they just do it. Yeah, give me a blood test, I want to be sure that I'm doing okay.
SPEAKER_00Yeah, I mean, I think uh um we are doing our level best to help people understand not only what our recommendations are, but what the basis for those recommendations are. So if you think about it, um your pre-existing level of cancer risk is really important to the outcome that you would have with a with a cancer screening test. If you're a young, healthy individual with no risk factors, um the ratio of true positives to false positives would be quite different, and you'd have a lot more false positives um than uh than true positives in that setting. And and then um uh you know, the impact of uh radiation exposure, I think, is something that one needs to consider. The radiation exposure is um well justified in individuals over the age of 50. We've looked at that. Um but um as you get younger uh uh it's more important to be thoughtful about that. So you've got a situation where the benefits are not as pronounced and the risks are a bit greater, and so we uh uh we are um quite determined to educate as much as we possibly can how these tests should be used. Um uh no doubt that we we can't control absolutely everything, but we we will be quite transparent about what we recommend and the basis for that thinking so that people can take a critical look.
SPEAKER_01When is the file control you think we'll we'll read? Is there a timeline you uh based on accrual?
SPEAKER_00You know, I'm not I'm not sure yet. It's uh it's a rolling basis accrual and we we keep going. So uh it's uh uh I'm not quite ready to to forecast uh a date of completion, but let's just say I can't wait. Yeah, yeah.
SPEAKER_01I mean it's it's a it's a it's a very interesting study. What what else is happening in that in the world of MSAT? Anything that you think listeners and viewers should be aware of uh aside from what we discussed that I may have not mentioned or covered?
SPEAKER_00Sure. I mean I think um a couple things. Um one is that the the evidence base that is being built for the category of MSAT is growing. Um our colleagues at Grail published Pathfinder 2, or I'm sorry, presented Pathfinder 2 initial results. That was that's their study and demonstrated the ability to detect cancers, including cancers early, just like we did in the Detect A study and in the Ascend II study. So we're seeing uh more and more evidence in total across the field from different um companies that the MSAD test um has a significant potential to detect cancer early. Uh on our front, I mean the the big news is we we launched CancerGuard, we've made it available to the public with a lot of education and and um and all the things that we talked about, but it is now available to to folks through their through their docs, through um through uh through CancerGuard.com, which routes um a request to a telehealth provider. So we're excited to to be out there. We're gonna be collecting data uh from our commercial experience as well, of course, in a de-identified manner, but that is another way to keep learning.
SPEAKER_01Well, um now you got me thinking maybe I should have the test done. But that would that would be admission of me that I'm I've turned 50. Have you? No. Did you have it done? What's that? Did you have you're not 50 yet, are you? Oh, I'm 60. I just look this young. Ah, okay. Well, then you must have had it done then.
SPEAKER_00I'm about to have it done. I've uh I've got a request in and we're scheduling mobile sabotics.
SPEAKER_01I should have done this podcast with you as we are reading the test results on the air.
SPEAKER_00Oh my goodness. Well, um I wonder if uh there's some restrictions on doing that in trying in terms of uh but it would be it'd certainly be fun, yeah. So I I will be um okay. I will be using the test uh myself, yes.
SPEAKER_01Well, I think this was helpful, Tom. I mean, I I'm trying to think if any other I'm trying to think from listeners and viewers' perspective, there anything specific. I think we covered what is the MSAT test, what you're looking. We talked about Falcon, we talked about, I guess, the shortcomings, uh, which is again, you know, uh, you know, how often do you repeat it? Right now it's annually, but you know, you you you wonder if it's too much, it's too little. We really don't know. I think Falcon will shed some light on this, but uh but not all. There will always be remaining unanswered questions, but nonetheless, it's gonna give us a lot of information.
SPEAKER_00Yeah, I mean, I I think we covered the topic. I would just say that um it it's a really exciting time. You know, we have we have unanswered questions, of course, we have a lot more to be learned. We all want more data and more publications and more studies. But the the ability to detect most types of cancer from a single blood test is is truly something you couldn't imagine you know a few years ago. And so I I am just ecstatic to get the opportunity to be a part of this field, and I'm convinced that we'll look back on this era as the beginning of of something that that's that's really impactful and meaningful.
SPEAKER_01Like a Tom Beer from Exact Sciences, thank you so much for coming on my show.
SPEAKER_00Thanks for the opportunity.
SPEAKER_01Great to see you. Okay, folks, thank you so much for listening. Thank you for being on this show, and thank you, Tom, for spending some time with us talking about MCED. And folks, please subscribe to the show, rate it, let your friends and colleagues know about it. You can find me on YouTube, Instagram, Twitter, TikTok, or Facebook. Just let others know about the show. And if you have some time, just a couple of lines of reviewing the podcast will go a really long way in making sure others know about it and they are aware of this podcast and what we have to offer. And before I let you go, I'm gonna leave you with a saying by Charles Kettering. My interest is in the future because I am going to spend the rest of my life there. Until next time, take care.