14 – The COVID-19 Pandemic’s Impact on Cancer Screenings
November 30, 2023

In the years since the COVID-19 pandemic began, cancer screening has changed, necessitating inventive strategies. Epidemiologists  Dr. Alpa Patel (Senior Vice President of Population Science, American Cancer Society) and Dr. Tina Clarke (Vice President of Epidemiology and Distinguished Scientist, GRAIL) return to The Cancer SIGNAL to discuss how the pandemic changed access to cancer screening, the impact it had on diagnosing cancer, and where that leaves the screening landscape today.  

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Kim  00:09
Welcome to The Cancer SIGNAL, a podcast presented by GRAIL, where we discuss the impact of early cancer detection, the science behind multi-cancer early detection and insight into how this approach has the potential to shift the cancer paradigm. I’m your host Kim Thiboldeaux. Today we welcome back to the podcast, our favorite epidemiologists, Dr. Tina Clarke and Dr. Alpa Patel. Go back and check out episode seven. It was titled “Exploring How We Address Cancer Risks” to hear them dig into that topic of cancer risk. But today we’re going to talk about the impact of COVID-19 and the pandemic on the average stage of cancer diagnosis. 

So to meet our guests, Dr. Alpa Patel is the Senior Vice President of population science at the American Cancer Society, where she oversees a team of approximately 50 research and study operation staff who use their research expertise in epidemiology and behavioral science to increase the understanding about the causes of cancer and how to improve outcomes after a cancer diagnosis. We are also joined by Dr. Tina Clarke, who is Vice President of Epidemiology and Distinguished Scientist at GRAIL. She joined GRAIL in 2016 and remains among its most tenured scientists. Before coming to GRAIL. She worked at the Cancer Prevention Institute of California, part of the Stanford Cancer Institute, running multiple NIH funded research projects, including the Bay Area Cancer Registry. Welcome to the show, Dr. Patel and Dr. Clarke. 

Dr. Alpa Patel  01:33
Thanks so much for having us.

Dr. Tina Clarke  01:35
Thanks for having us Kim. We’re excited to talk about this.

Kim  01:37
Excellent. Good, I am too. Dr. Patel, I’m going to start with you. Let’s just do some level setting for our audience today. Before the pandemic turned everyone’s world upside down, what was the standard cadence for cancer screenings that are generally available today?

Dr. Alpa Patel  01:54
So I mean, obviously, it depends on a lot of different factors. But overall, we saw that, you know, in the, probably five years prior to the pandemic, there was, you know, pretty consistent trend. For instance, for breast cancer, about two thirds of women were going to get their, were meeting recommendations for mammography. It was higher for things like cervical cancer, over 70% of women, about 60% for colorectal cancer screening tests, if we look against ACS guidelines. So we still had work to do. And as you noted, the pandemic really turned everything upside down in terms of the progress we were making in terms of increasing screening.

Kim  02:35
Okay, so, you know, one could say fairly low, you know, rates of screening pre-pandemic right before our world was turned upside down. So let’s talk about the impact of the pandemic. So we were all told to stay home right in the spring of 2020. I’m sure that the first thing to be canceled were non-urgent appointments or those that may have been considered preventative, so appointments like your regular dental screening, maybe your basic, annual physical and screenings like mammography and colonoscopy. So let’s talk turkey, how long were these cancer screenings unavailable? When did people start rescheduling? When were they able to reschedule them? Or do you think many people still haven’t rescheduled them?

Dr. Alpa Patel  03:19
I think some people, it got to the point where they were far enough along, because it was several months before you were able to reschedule. And it depended on what that screening test was. So things like for instance, a colonoscopy which required, you know, having anesthesia and going into a hospital setting and so on, there was a longer delay there to get people back in safely. And obviously, also competing resources on the health care system to be able to support those kinds of what were considered non-essential. So we saw about a 10% steep decline in the early months of the pandemic for breast and cervical cancer in terms of rebounding. So if we look at, you know, there was a sharp decline and then overall, we’ve seen if you look at the year after an overall 10% lower rate for breast and cervical cancer, and even higher than that for colorectal cancer. So what does that mean? That means yes, I think that there were definitely people who, they were so delayed that they just waited till the next year, by the next year, vaccines were available, it was safer, there wasn’t as much of a burden on the health care system because of COVID. So then people were able to get back in.

Kim  04:34
Got it. Got it, it’s helpful to just kind of kind of level set on that. And we all had a lot of theories Dr. Clarke about this. How many people were not getting screened, what was the impact, but now we actually have a study. So Dr. Clarke, tell us about the study. It was published in The Lancet this summer. It was titled “Changes in cancer diagnoses and stage distribution during the first year of the COVID-19 pandemic in the USA, a cross sectional, nationwide assessment.” So first of all, break that title down for us. What was the study investigating?

Dr. Tina Clarke  05:09
So this paper was published this summer. And I think we epidemiologists were keenly interested in what was this natural experiment of the COVID disruption in screening going to do to the population trends in cancer. We were really interested to learn if the stage distribution of cancers diagnosed before and after this COVID disruption in screening was going to change. And then obviously, we’re really interested in, you know, the further impact of that any kind of stage at diagnosis change on cancer deaths, or on cancer outcomes. So this data has been very keenly anticipated by the, by the cancer research community, because it represents, you know, what amounts to a natural experiment, and what happens if you all of a sudden take cancer screening away, what happened. So this paper used data from a cancer registry called the National Cancer Database. The National Cancer Database is sponsored by the American College of Surgeons, and the American Cancer Society. And it collects a really rich set of data from each and every cancer patient who is diagnosed at more than 1500 hospitals that are accredited by the American Cancer College of Surgeons. So it’s not the whole population of the US, but it’s very particular hospitals that are, that are accredited by the American College of Surgeons. So it’s a really good resource. It is available before the population based cancer registries, which is the kind of cancer registry that I used to work at that cover the entire geographic population. Those are really important data that I’m going to speak about in a little while. So the NCDB data, we were able to look monthly at new cancer diagnoses. And we looked at what that pattern looks like. So basically, if you could look at the graphs that they published in this paper, and I’ll talk you through them, so you can imagine what they look like, we see very consistent rates of stage one, and stage four cancer up until about April, March, April of 2020, when as we all remember, we were told to stay home. All these appointments got canceled, and then you see a sharp decline in stage one cancer diagnoses, right during those months, and you see a shift where those cancer diagnoses are now being diagnosed at later stages. So we see a little bump up in, in the later stage cancer. So it’s pretty amazing to imagine that these things can change that quickly. But then the good news is they, they come back to the same levels within a few months, which we would imagine has to do with as Alpa discussed standard screening appointments, being able to be rescheduled. So the paper was able to look across different cancer types, each of which have their own screening program. So they looked at breast cancer, colorectal cancer, prostate cancer, lung cancer, again, each of which has a separate, you know, set of rules for who should be screened on what timeline and with what technology. But we see a pretty consistent trend of a, you know, a dip in total diagnoses, because people are just not able to get any kind of medical appointment. But we really see it strongly in the stage one diagnoses where we would expect those cancers to be picked up in asymptomatic patients through screening appointments. The other thing that the paper shows, which is really, you know, heartbreaking and we know is such an enormous problem in our country is that these changes were more pronounced in you know, in areas that are, we call them socially deprived geographic areas. So we’re able to take neighborhood information and know that these are neighborhoods in geographic areas that have lower access to care. It’s harder to access the medical care that you need. So we see even more of a stage distribution change in socially deprived neighborhoods.

Kim  09:39
Wow. So that pattern has continued even through the pandemic to see a greater impact on these marginalized communities is what you’re saying. 

Dr. Tina Clarke  09:48
Right. So super interesting. So you know, other places in the world that reported you know, what happened during COVID. Again, we saw that it disrupted the entire cancer diagnostic chains because people couldn’t get appointments, even for, you know, to get their symptoms checked out outside of the screening programs. You know, I think we see this bump up in stage four because those diagnoses were delayed due to just not being able to get a routine doctor’s appointment book, because the whole screening that, as you said, Kim, that screening appointments and non-urgent medical appointments, were probably the first to get disrupted. We also see stage one, cancer diagnoses, you know, really shift with the natural experiment of screening programs being pulled out from underneath us.

Kim  10:39
Right, it right. Interesting that that idea of a natural experiment, Dr. Clarke. But what so, you know, the conclusion, what does this mean for screening and diagnosis? I mean, is it our screenings, the ones that we currently have available, which are only a few, right? Is the conclusion that we know that they’re working, we have to keep them on track? And, and then talk about, just explain what this idea of stage shift is. I want to make sure we’re breaking down that and what does this mean for sort of that the importance of stage shifting? 

Dr. Tina Clarke  11:06
Yeah, so let me talk about that a little bit. So, one thing that Alpa and I really talk and think about a lot as we, especially as we contemplate a future with technologies, like the GRAIL Galleri test, that allow us to screen simultaneously for multiple cancers is that we can really talk and think about cancer differently. So all, before but you know, all human beings, and this sadly has to do, I think we talked about this in our last podcast about the aging of your DNA, as you just move through time and your DNA accumulates mutations, just a large again, largely due to aging, all human beings are at measurable risk of developing any kind of cancer. So we know this in our daily life and talking to people like they don’t get to pick if they get cancer, and they don’t get to pick what cancer type they get. All human beings are at measurable risk of any kind of cancer, so talking and thinking about cancer screening and prevention, and things you can do to reduce your risk of being diagnosed with cancer, or with a late stage cancer, should you get cancer, you know, we’ve really divorced that into different, we’ve told people that you have to do this for breast cancer, and you have to do that for colorectal cancer, and you do this for lung cancer, but you know, those are all separate programs and separate and separate things that we tell people to do. And so and then when we look at these statistics, we, we look at them separately. 

But I like that the idea in this, in this paper in this research and in this topic of what happens when the natural experiment of taking medical care away happens because it does allow us to look at the whole, the whole impact of both screening programs and you know, symptomatic diagnostic medical care on the population burden of cancer. And again, what we saw here with this natural experiment, of we took that all the way we restricted people’s access to both screening that occurs in healthy asymptomatic people who are told to do a routine annual screening appointment, and we took away, it was difficult to get a more urgent appointment for, for getting symptoms checked out if someone was having any kind of abdominal pain or you know, blood in their sputum, or blood in their stool, or what have you, or any of the unexplained weight loss, any of those kind of, you know, really important cancer symptoms, like it was hard for people to get that. 

And what we saw was the total distribution of cancer stage shifted away from early stage cancers and towards late stage cancers. And then as the impact or as the, you know, pandemic restrictions loosened and appointments became available, and people were able to get that whole totality of services back, we saw them come back to where they were before. So again, it does constitute a natural experiment and the stage shift that we saw in the population was that when people couldn’t get either screening or symptoms checked that cancer is diagnosed later. And again, we don’t have any data at this time as to what does that mean for people’s, you know, longevity, mortality or outcomes, but our suspicion will be that you know, when cancer is diagnosed later, especially after it has metastasized at stage four, for most cancer types, that is not good and that does usually result in a short course to death. 

Kim  15:01
Yeah, so Dr. Patel obviously that’s this took us in a direction the opposite direction, right? That we want to go. We want to be diagnosing earlier stage, earlier stage. So Dr. Patel talk about how you think the pandemic changed how doctors diagnose and treat cancer, where are we now? Are we back on track? Are we still dealing with the long-term impact of not doing those screenings?

Dr. Alpa Patel  15:23
I think we’re I think we’ve made tremendous progress in getting people caught back up and into that regular cadence. I think the challenge still left in front of us is those individuals who weren’t necessarily getting screened on regular, on a regular cadence before the pandemic, we still have a lot of work to do, in terms of getting overall screening rates higher. But I do think, you know, as Tina described, you know, even with the evidence of we saw that stage shift, and we’re seeing recovery from that stage shift back to what it was pre-pandemic, we are seeing that people are getting back to their screenings, post-pandemic, and we’ve seen rates of screening return to those of the pre-pandemic period, for most common types of cancer for which we have screening tests. In terms of then treating cancers, I think we’re seeing some changes, some of which may persist, and may be a really good shift. So obviously, during the pandemic, you couldn’t get your screening tests done through a telehealth appointment. But you could actually use telehealth to access health care, you could use telehealth to also explore options that were you know, possibly shifting to an oral medication, because you couldn’t get in for an infusion therapy. And you know, and previously, that wouldn’t have necessarily been an option that would have been explored for someone who had difficulty getting to an appointment. But the pandemic actually shed light on being creative and looking at other ways to treat someone from afar because they couldn’t come in for that kind of in person treatment. So hopefully, we’ll see some of that continue to reach individuals who have barriers to get into treatment, because they can be treated from a distance. But, you know, I do think that it’s challenging us to think about how we should be both diagnosing and treating cancers moving forward. 

Kim  17:31
So Dr. Patel, so we’re getting folks back on track, we’re seeing improvement, we’re getting back to potentially pre-pandemic levels, hopefully, we’re gonna get better than pre-pandemic levels. But talk a little bit more, we talked about our sort of underserved, marginalized communities, communities of color, who are facing challenges even before the pandemic, I think the pandemic laid bare many of the access challenges, trust in the health care system, so many issues for these marginalized communities. What are we seeing specifically in those communities? Sort of, I’d like to say post-pandemic, right post-pandemic, and are we seeing numbers improve? Are we going back to the same rates? What do we know?

Dr. Alpa Patel  18:10
So we’re definitely seeing numbers improve. Do they improve? Are they improving equitably? No, we’re still seeing that there are those disparities that existed before the pandemic. And that really has to do with a lot of barriers that we still have in place post-pandemic. So, you know, the pandemic did shed a lot of light on these disparities, on difficulty for some individuals to access health care, compared to others. Have we done what’s needed to be done to be able to break down those barriers to get to a more equitable state? No. So we’re seeing overall increases, but we’re not seeing the increases equitably across different populations.

Kim  18:56
Okay, got it. There’s still work to do. Could you also briefly touch on cost – in terms of the cost comparison in treating cancer when it is found in early stages versus in later stages?  

Dr. Tina Clarke  19:09
This paper that was published that showed this bump up in stage four cancer diagnoses when we diagnose cancer at stage four, compared to stage one, we can spend up to four times more treating it. So the surgery is more complex, the kind of chemotherapy that we have to use to try to treat stage four cancer is really different and can be more expensive. So we know that when cancer is diagnosed later that has economic impact on the cost of treatment. And then of course, outcomes tend to be much worse. People are more likely to die. So not only do we spend more money to try to treat this cancer, but then the outcomes are even poorer. When you take the social impact of a late-stage cancer diagnosis. Let’s pretend we’re talking about, you know, a breadwinner in their family who now cannot work, the kind of impact that has on a family. I mean, it’s just the ripple effect of late-stage cancer diagnosis is extreme. And we don’t really talk about that enough when we talk about, you know, the importance of screening and early diagnosis is the economic impact and the impact on, you know, yeah, the economic impact on families too.

Kim  20:26
On families, and we have the cost. But we also have the cost, meaning the toll that late stage takes on the family, the emotional part of dealing with that diagnosis, the social part. So you know, taking care of kids in the family, keeping a roof over, you know, over people’s heads, right. So there’s this sort of emotional and financial and spiritual and psychological impact, in addition to the financial toll that that late stage diagnosis takes on a family. 

Dr. Tina Clarke  20:55

Kim 20:56
I want to ask both of you, as we think about the challenges we had pre-pandemic, and then the cumulative challenges that happen during the pandemic, what are some of the innovative steps that we can take to sort of bridge the gap in cancer screening? What are the, what are the cool ideas out there, the creative ideas out there, models that we can look at to increase the rate of screening overall in our country? 

Dr. Alpa Patel  21:20
Well I mean, I think, you know, Tina touched on this point that we don’t get, you know, we’re at risk for any type of cancer, we don’t get to pick what kind of cancer we may get if we do get cancer. And so when we think about you know, you know, I go to the doctor regularly just had, you know, I had my mammogram last week, a couple of weeks before that I had my physical which included my five year pap test. You know, and so on. I’m having to take a half day off for different things. And you think about, again, if we think about through the lens of health equity, how do we get to a more systematic and organized way of packaging this so that in the healthcare arena, and with the patient, we’re really talking about the entirety of your cancer risk, we’re not saying you need to go do this for colorectal cancer, you need to go do this for breast cancer, this for lung cancer, and this for cervical cancer. And if you’re a man, this for prostate cancer. We’re actually coordinating care in an efficient way where, wouldn’t it be great if we could get all of the things that you need to get done for cancer detection done at a single visit? And you know, and there are some, you know, really innovative studies that are showing in other countries where this kind of coordination of care is happening. And it actually does result in overall increases in your adherence to your cancer screenings as a whole. And I think in particular, if we want to combat the challenges of inequities in access to care for underserved populations, for those that there are access issues, think that coordination of care will be critical in being able to increase broadly screening and early detection for those harder to reach populations. 

Kim  23:18
Music to my ears.

Dr. Tina Clarke  23:20
Totally agree. This paper we were just looking at together, Kim. Again, this just doesn’t sound like rocket science. But it was a study from Israel. And they said, hey, we’re gonna invite, we call it, we’re gonna call it a one stop shop for cancer screening. Let’s invite people to come in just once and we’ll give them all the guideline-based cancer screening that they might need. So Alpa referenced what those things are, and how they vary for men and women, but let’s get them in, in one afternoon, and get all those appointments done at the same time. Again, not rocket science, if you do that, people’s utilization, people are more likely to be up to date with their screening. And we’re talking about communities with, with disparities. I mean, if you’re working a job on a shift with a schedule, and maybe you’re paid hourly, like that makes a huge difference, to be able to say, you know, I need to, I need the afternoon off, rather than I need like three different days off. And, Kim, you and I were talking before the podcast, too, about, you know, sometimes you take the time off your job to show up for these things, and then they keep you waiting for an hour and you’re like, I can’t, I gotta get this done. But I gotta get back to my job, or I gotta pick up my kids from school or what have you, or. So I think, you know, our system does not make it easy for people to, to be up to date with all the things that they do. But we also need to be more creative and innovative in making it easy for people. And I think that’s a big challenge for our American healthcare, you know, fragmented healthcare system to take on.

Kim  24:58
Yeah, really great comments. Let’s use this show as a platform to bring those great ideas forward, creative ideas forward. Hopefully, some of our listeners will want to work together with us to bring these solutions forward to all people but especially to those marginalized communities who are facing a whole other layer of challenges. So let’s continue the conversation. Other ideas, Dr. Clarke, other ideas about ways that we can perhaps be supporting one another or encouraging each other to get our screenings at different people are approaching screening age, you know, thoughts about that just even your own personal experience?

Dr. Tina Clarke  25:39
Yeah absolutely, so I am I just entered official screening age on a few things. I won’t tell you what birthday I hit, but-

Kim  25:46
I’ll just say welcome to the club.

Dr. Tina Clark  25:49
I’m here in the club. And I think having the conversations you need to have with your friends and if you’re part of groups of, you know, so like a book club or a I have a Mahjong club and we like to talk about the things we’re doing but just a really practical stuff about which doctors are you going to which, you know, which appointments are you getting, you know, what, where are you getting your mammogram, done – that type of thing, like really supporting each other to help make this is, you know, as convenient as it is, you know, as easy as possible and being accountable to each other, I think, really helps. I think it’s really hard in our fragmented health system to make it a social event, but if you can. You certainly can’t schedule mammograms together and that would be really weird. But I’m actually today getting my Galleri test for the very first time. GRAIL has pulled up a mobile phlebotomy unit outside our building, and I invited a couple of friends to come get a test with me, and we’re gonna have lunch afterwards. So I would, I would hope that that invitation, encouraged them to, you know, to, to take action and, and pull the trigger and get they were interested in getting a Galleri test anyway. And, again, that’s really challenging in our fragmented health system, but we just got to do whatever we can as friends, and family members to, you know, be supportive, be accountable and help make sure that our loved ones get these crucial cancer screenings and that they’re up to date.

Kim  27:24
Yeah, it’s, it’s a great topic. And you know, look, we have the holidays coming up, right, we’re all going to be around the table talking with one another. So also maybe a good time to remind folks about their screenings, a good time to talk a little bit about family history, and risk, things like that, when we’re together as a family. Alpa, other thoughts about how we can be motivating each other?

Dr. Alpa Patel  27:44
I mean, I think that Tina touches on the accountability partner. We know from a lot of other behavioral studies, we know that an accountability partner for things like exercise works. So it makes a lot of sense that those types of things would work here. You know, every time I leave an appointment, whether it’s an annual physical or a mammogram or, you know, I’m getting my blood work done, I always make a point where when I get in the car, as long as the car ride takes me, that’s how many phone calls I make to remind other people in my life to do the same thing. Hey, I just left this appointment. Did you get yours? And it’s, you know, it’s just that reminder that makes people feel more accountable, versus you know, having to remember themselves. So I think there’s just a lot of things, but I think the bottom line is really opening up communication, and making it a more regular part of what we talk about. We talk about hobbies and traveling and families, but we don’t talk about our health regularly in social settings. So working to normalize that conversation.

Kim  28:47
Yeah, terrific. Great advice from both of you. Thank you. I appreciate both of you joining us today. You know, I think one thing I know we can all probably take away from the conversation today is no more excuses, everybody, we need to get out there, you know, get our, get our cancer screenings, and, you know, keep on top of our, keep on top of our health care. So let’s, let’s keep talking. I appreciate both of you joining today. This is The Cancer SIGNAL presented by GRAIL. I’m Kim Thiboldeaux. Please rate and review our podcast and be sure to subscribe to learn more about the impact of early cancer detection on future episodes. Thank you.


Based on a clinical study of people ages 50 to 79 around 1% are expected to receive a cancer signal detected result, which includes predicted cancer signal origins. After diagnostic evaluation, around 40% of people are expected to have a confirmed cancer diagnosis. 

The Galleri test is prescription only. The Galleri test is recommended for use in adults with an elevated risk for cancer, such as those age 50 or older. It is not recommended for individuals who are pregnant, 21 years or younger, or undergoing active cancer treatment. Galleri should be used in addition to routine cancer screening. Galleri does not detect a signal for all cancers. False positive and false negative results do occur. For more information, including important safety information, please visit galleri.com


Important Safety Information
The Galleri test is recommended for use in adults with an elevated risk for cancer, such as those aged 50 or older. The Galleri test does not detect all cancers and should be used in addition to routine cancer screening tests recommended by a healthcare provider. Galleri is intended to detect cancer signals and predict where in the body the cancer signal is located. Use of Galleri is not recommended in individuals who are pregnant, 21 years old or younger, or undergoing active cancer treatment. Results should be interpreted by a healthcare provider in the context of medical history, clinical signs and symptoms. A test result of “No Cancer Signal Detected” does not rule out cancer. A test result of “Cancer Signal Detected” requires confirmatory diagnostic evaluation by medically established procedures (e.g. imaging) to confirm cancer.

If cancer is not confirmed with further testing, it could mean that cancer is not present or testing was insufficient to detect cancer, including due to the cancer being located in a different part of the body. False-positive (a cancer signal detected when cancer is not present) and false-negative (a cancer signal not detected when cancer is present) test results do occur. Rx only.

Laboratory/Test Information
GRAIL’s clinical laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA) and accredited by the College of American Pathologists (CAP). The Galleri test was developed, and its performance characteristics were determined by GRAIL. The Galleri test has not been cleared or approved by the Food and Drug Administration. GRAIL’s clinical laboratory is regulated under CLIA to perform high complexity testing. The Galleri test is intended for clinical purposes.