Melanie Cole, MS (Host): Cancer rates in young adults are rising, especially for colorectal cancer. What's happening? And what should younger people do to keep themselves healthy now? Welcome to It's Your Health Radio with Henry Mayo Newhall Hospital. I'm Melanie Cole. Joining me today is Dr. May Lin Tao. She's a Clinical Associate Professor of Radiation Oncology at the Keck School of Medicine, and she's the Medical Director of the Keck Medicine of USC Henry Mayo Newhall Hospital Cancer Program.

Dr. Tao, thank you so much for joining us again. You're a great guest. And now we're talking about rising cancer rates in young adults. Can you tell us a little bit of an overview of the current trends in cancer rates among younger adults? What are some of the most common types you're seeing?

May Lin Tao, MD, MS (Guest): A year or so ago, probably the most informative article that came out about this subject was published in JAMA Network and was picked up by a lot of news lines because of pretty dramatic findings. So this looked at 17 National Cancer Institute registries. They had over 500,000 cases, and they were looking at what was the rate of cancer diagnoses in people under 50.

We generally use 50 as kind of a cutoff of when we would characterize something as not early onset or if it's less than 50 early onset for that diagnosis. And what we saw interestingly, that overall the incidence in cancer was rising in this early onset group, again defined as under 50, but was even more interesting is that the younger people it was rising in were actually those in their 30s versus those in their 40s.

So the rate of rise wasn't happening in those between 40 and 50. The rate of rise was happening between those 30 to 40. Which is actually quite early onset. It seemed like it was higher in women versus men, and in certain minorities like American Indian, Alaskan Indian, Hispanics, and Asians. And it was, not rising really in non Hispanic whites.

If you looked at actually just in terms of absolute numbers, what was the highest number of early onset cases diagnosed, let's say, a couple of years ago, if we're kind of looking at this trend. It was actually breast cancer, just in terms of absolute numbers. But what was the dramatic thing was that the rate of increase, meaning, you know, a baseline number that was very, very small and how quickly it rose, even at, even though in absolute numbers it's not very, very high, it was a rapid increase, is those that were developing cancers of the gut, or what we often call colorectal cancers.

And that was alarming, and started a whole series of considerations for why are we seeing this, and why are we seeing this in this particular, what we call birth cohort, meaning the 30 to 40 year olds.

Host: This is fascinating. And so that is my question. What factors do you believe are contributing to this rising rate? Why are we seeing this? I'm sure it's multifactorial.

And I'm sure that it's a complex question, more complex than you and I could solve in this podcast. But in your opinion, your expert opinion, where do you see as some of those factors?

May Lin Tao, MD, MS (Guest): Well, we know a couple of risk factors for cancer in general. So logically, we kind of look to those and see what is the association between those and the cancer incidence rise that we're seeing. So the Western way of living, particularly those, interestingly, where the level of socioeconomic status for the general population is higher than let's say third world countries, have a huge problem when it comes to their diet, what they're drinking and their environmental pollution. One of the things that we're seeing at pretty early ages, in fact, the American Pediatric Society has sort of put out an alarm notice about this, is obesity.

And that is of linked to what's considered a typical Western diet of more processed foods, red meat, added sugars, along with things like a lifestyle in which we're not sleeping well, we're drinking more, we are probably not exercising as much as we can, and as obesity seems to be more of a prominent problem in pretty young people, it seems to be tracking also with this increased rise in gut cancers in particular. So the thought is that, at least a significant contributor to what's going on. We know that obesity onto itself at any age, if you will, will be a correlate with cancer development. But if we're talking about obesity in a state that's occurring at a pretty young age, so childhood, that's a long, long time to be in this state, which is enriching the likelihood of getting a cancer.

And so, you're going to see the rising cancer in an earlier age than if obesity occurred a little later in life, and you would see the cancer manifest itself in the 50s plus.

Host: So, then I guess the big question here is, we've obviously had all these screening recommendations over the years, over 50 unless you've got family risk of colorectal cancer, breast cancer, you start your mammograms, 45, whatever, all these recommendations we've had all these years. Now that this is trending a little bit towards the younger adults, what do we do about detection?

Do we start breast cancer screening on younger women, especially if there's a risk? Colon cancer, colonoscopies for younger people. What do you think we should be doing about this?

May Lin Tao, MD, MS (Guest): So, a year or so ago, I think it was in 2021, understanding that the average age for colorectal cancer was trending down, the U.S. Preventive Task Force actually changed the guidelines to say that 45 was now the new 50, meaning that people should be getting screening colonoscopies starting at the age of 45, which was again, a reaction to what we were seeing just in general numbers.

But what we've learned more recently, if you actually look at the cohort effect that's happening, meaning where in this early onset period is this rise being seen, it's actually, as I said, between 30 and 40, so that decade. So, really even dropping it down to an age of 45 isn't really going to make that difference.

The other challenge is because people in that age group are generally not screened because they're so young, they're presenting in a state in which they're already fairly symptomatic. So, they're being diagnosed at an early age and they're being diagnosed with more advanced disease that's less curable.

I just want to also point out, though, that even though we're seeing this increased rise in this group, just in terms of absolute numbers, which is something I mentioned earlier with regards to breast cancer, which is actually the disease, or cancer group in which we're seeing the highest number in terms of absolute numbers, for this younger cohort, meaning less than 50.

The absolute numbers are still not that high. What's dramatic is a sudden uptick. But even if you look at all of colorectal cancers, by far, there are many, many, many more being diagnosed in the typical age range, so 50 and above. So honestly, dropping it down to 45, I don't know if it's really going to make that much of a difference, but you know, we sort of need time to absorb this information, learn more, and then it takes a process to make those changes.

Host: Dr. Tao, can you please tell us about a recent story in the New York Times and other news media about a possible new blood test for detecting colon cancer?

May Lin Tao, MD, MS (Guest): So, one of the things that's challenging in colorectal cancer screening, is that we have realized that there are a lot of notable barriers. Probably only 50 to 60 percent of patients who are actually eligible for screening, end up following through with any of the suggested types of screening. And that's in part because one colonoscopy, which is the gold standard, folks don't like to go through procedures. There's the prep that takes a couple of days with laxatives. It's uncomfortable. It's a procedure. And even the other stool based tests for a lot of folks, they feel kind of squeamish about it and it requires actually that you do it more regularly, anywhere from one to three years, depending on which stool tests you do. So there's been a lot of interest in whether or not we could do something that was just a lot more acceptable, and easy to do, and therefore get more patients screened and hopefully save more lives.

So Guardant, which is a leader in kind of this industry at looking at blood based testing for cancer screening or monitoring of treatment when a person actually has cancer, has developed a new tool. It's currently described as a quote, a lab based tool, but it is undergoing a process for FDA approval for marketing as a screening test, that is, simply that, a blood test, just a blood draw for a patient, or a well person looking to be screened. And it looks actually at DNA fragments in your blood of tumor that may be circulating in your body. So, a recent study showed that it's actually quite sensitive, meaning that if you actually have a cancer or a very large precancerous lesion, about 83 percent of the time it'll get picked up.

And it's reasonably specific, meaning that if it does show that there is this presence of these DNA fragments, that 90 percent of the time it turns out that you actually do have an early colorectal cancer or a large precancerous lesion that needs to be addressed.

Host: Do you think that this is something that we will see into the mainstream?

May Lin Tao, MD, MS (Guest): It is definitely where the field is moving towards. Tests that have ease, that can be done in a large group of patients, that there are no sort of system, or fear reasons for accessing them. We're still early in the process of getting things like FDA approval for marketing. The cost is not yet well worked out. Hopefully it'll be in line with the cost of screening tools that we currently have in regular motion. But the other thing is these blood tests are different from the gold standard screening test in that they are picking up things early. So what we call early detection as opposed to preventive.

So the reason why colonoscopy will remain the gold standard, I believe, is that it is actually a preventive maneuver as well as an early detection maneuver, meaning that polyps that have a risk for becoming cancerous can be identified and removed as part of the procedure. In fact, colon cancer is often described as one of, quote, the most preventable, yet perhaps the least prevented because of the barriers for actually screening, but also reminding us that colonoscopy, if you do undergo it, can actually prevent the cancer from even developing, unlike these blood tests or even the stool tests that are sometimes used as alternatives.

Host: As we get ready to wrap up, Dr. Tao, I'd like you to speak to other health care providers and public health officials working together to raise that awareness, which is what you and I are doing, and then to the younger individuals that we're talking about here today and the steps that you really want them to hear from the expert that you are and what they can do to hopefully reduce their risk of getting some of these cancers that we're seeing trend towards the younger folk.

May Lin Tao, MD, MS (Guest): I think it's really important, as you mentioned, to really think about this in sort of a public health perspective. And thinking about this as a long term lifestyle issue. Because likely what this is, is something that is related to something we're ingesting, some behaviors we're having, as well as probably some exposure to environmental toxins or chemicals.

I mean, there's really a stew out there, right? But those are actually much harder to study, because how do you actually measure the level of environmental toxins or chemicals? Do you do recall from people who were exposed at a very early age? That's just something very, very difficult to both measure and control.

But what we do know in a very basic way is that the way we eat and our Body Mass Index, our level of activity, and when that's occurring, meaning in a, in a positive way, needs to be really addressed. And that's how you're going to really impact a large population. So the education really needs to start at a very, very young age.

And in fact, the, as I mentioned before, the American Pediatric Society, they have said that that kind of counseling needs to occur as young as when children are toddlers. Of course, a lot of that is to parents, but we're really talking about a whole lifetime of behaviors and dietary patterns.

Host: Thank you so much, Dr. Tao. You are an excellent educator and a great guest as always. Thank you so much for joining us and sharing your incredible expertise today and for more information on important cancer screening guidelines, visit henrymayo.com/screening. And you can learn more about cancer screening and get other health tips at Henry Mayo Newhall Hospital's online

 free online health library, and you can find that at library.henrymayo. com. That concludes this episode of It's Your Health Radio with Henry Mayo Newhall Hospital. I'm Melanie Cole. Thanks so much for joining us today.