Chuck Cohen: Welcome everybody to another episode of Driving Dentistry Forward, Benco Dental’s podcast with interesting leaders in dentistry, all focused on driving dentistry forward.
Today, my guest is Dr. Ross Kerr, a professor of oral medicine at New York University and one of the leaders in the whole discipline of oral medicine.
In honor of Oral Cancer Awareness Month, we thought it would be great to reach out to Dr. Kerr and ask him a little bit about oral medicine, oral cancer, and how dental professionals can be better at spotting it and dealing with it in their practice.
Welcome, Dr. Kerr. Thank you very much for being here.
Dr. Ross Kerr: Thank you very much for having me. I appreciate it.
Chuck Cohen: Excellent. I was hoping you could give us just two sentences on your background and really focus on this idea of the discipline of oral medicine, which I think for most of our listeners would probably be something they may have heard of but are a little unfamiliar with.
Dr. Ross Kerr: Yeah, happy to do that. I am an oral medicine specialist at NYU College of Dentistry. I’ve been there for 25 years.
What is an oral medicine specialist? Well, oral medicine is the specialty of dentistry. It recently became an official specialty through the American Dental Association about a year ago now. It’s the specialty of dentistry responsible for the oral health care of medically complex patients and the diagnosis and management of medically related diseases, disorders, and conditions affecting the oral and maxillofacial region. I read that directly from the American Academy of Oral Medicine website because I wanted to ensure that I give you the absolute accurate.
What I do is I see patients with oral mucosal diseases. That includes oral cancer and what we call oral potentially malignant disorders. I take care of patients who have dry mouths. So, I’m rather like the dermatologist to the lining of the inside of the mouth and have expertise in the dental delivery for patients who have other medical conditions and medical diseases.
Cancer patients are one of my favorite groups, and orofacial pain, which is a crossover with another specialty in dentistry. That’s what I do. There are about 250 of us in the United States and mainly in large cities and medical centers.
Chuck Cohen: Excellent. How did you get interested in this subspecialty of dentistry? Especially because when you first got into it, it was not an official specialty.
Dr. Ross Kerr: That’s right. Oral medicine has been around for a long time. The American Academy of Oral Medicine was founded in 1945. So, it’s been around for a long time. Much of it is related to the politics of having additional specialties within dentistry. So, that’s part of it. But we’ve been a very active group for a long time. We finally managed to get through the application process along with some others. So that’s great news.
I got interested in oral medicine when I was a dental student at McGill University. My mentor, Dr. Martin Tyler, an oral medicine specialist who trained in the Navy and was a very inspirational teacher, got me interested. He introduced me to one of his colleagues, who introduced me to the UW program, the University of Washington Oral Medicine Program. That’s where I went and did my oral medicine training.
Chuck Cohen: I’d imagine that what you do is more on the science side of dentistry, and a lot of us think of dentistry as sort of a continuum between art and science, with art meaning, however it looks and science, meaning the actual scientific end of it. I would assume that the oral medicine specialty would be more on the scientific end. That must be fascinating to research and look at on a day-to-day basis.
Dr. Ross Kerr: Yes, absolutely. I’m very much, first and foremost, a clinician. I see patients, but yes, I do conduct research, and there is a lot of ongoing research in the area of oral medicine. I’m an academic. I teach my students. I’m trying to train the next generation of dentists. We have at NYU approximately 8% of all graduating dentists. We have a class of about 400. So when I look back on it, I’ve probably trained 10,000 dentists to go out and look for cancer. That’s an area that I feel very good about.
Chuck Cohen: Well, on behalf of the industry and the general population, thank you for serving in the dental research and dental education area. When we think of dentistry, we often think of the dentist around the corner. But the unsung heroes of dentistry, in my opinion, are the researchers and the professors who find the new cures, the new products, and how to take better care of our oral health in America, as well as train the next generation of dentists. So, thank you for that.
Dr. Ross Kerr: You’re welcome.
Chuck Cohen: Let’s focus a little bit on oral cancer awareness. It is Oral Cancer Awareness Month. One of the things that I wanted to make sure everyone understood is there’s more than one kind of oral cancer. I was hoping you could walk us through that a little bit.
Dr. Ross Kerr: Okay. First of all, what do we mean by oral cancer? Typically, the connotation is it is cancer that grows within the oral cavity, involving the tongue or the insides of the cheeks or the gums or the bones making up the mouth’s structures. But it also may include oropharynx cancer. The oropharynx is connected to the oral cavity.
Essentially, the oropharynx is the very back part of the mouth, and it’s the backside of the tongue. The throat or the pharynx is made up of three structures: the oropharynx, the nasal pharynx, which is above the oropharynx (that’s essentially where the nasal passages go), and then the hypopharynx is below the oropharynx, and then below that is the larynx, which is also technically part of the throat.
In terms of these sites, the most common type of cancer is called squamous cell carcinoma. That essentially is a skin cancer of the lining mucosa of the oral cavity, the throat, and the larynx. The cancers begin in that lining mucosa. Now, there are other types of cancers, which make up less than 10% of all oral cancers.
These are things like salivary gland cancers. These are sarcomas, leukemias, lymphomas, and mucosal melanomas. But they comprise, as I said, a very, very small fraction. The ones encountered mainly by dentists or hygienists would be squamous cell carcinoma.
Chuck Cohen: Got you. Just talk for a minute about or a short time about two things that I find fascinating. Number one is the amount of oral cancer and related oral cancers out there and how prevalent they are. The second thing is how treatable these cancers are when they’re caught early in the process.
Dr. Ross Kerr: Okay, that’s a great question. In the United States, based on the data supplied by the National Cancer Institute, there are estimated this year to be between 55 and 60,000 cases of oral and pharyngeal cancers, and about 25,000 of those are in the oral cavity proper.
When you look at the statistics about what stage they are at at the time of diagnosis, you see a relatively small proportion; about a third of them are actually in early-stage disease. And early-stage cancer is largely cancer that is just in the primary location where it started.
So, let’s say the most common site in the mouth is the tongue. And let’s say it’s a tongue cancer. That means that it’s cancer that is small, less than a certain dimension, and there are various factors I’m not going to get into, as opposed to a more advanced cancer that has gone from the primary site that metastasizes into the regional lymph nodes in the neck and then ultimately to distant organ systems. They comprise two-thirds of cancer.
Advanced cancers are more common than early cancers. When we look at the stages, we see that patients with earlier cancers, smaller cancers in the primary site, are more amenable to treatment. Those patients have better survival statistics than people who have advanced cancers. So, it makes sense. You can’t generalize it to everyone’s cancers. But overall, if you have an earlier cancer, it’s detected earlier, then most likely you’re going to survive longer if you get the treatment you need.
Now, one other thing that I should mention is that most oral cavity cancers are all preceded by these pre-cancerous changes, which aren’t cancer yet, and these are known as oral potentially malignant disorders. This is a group of diseases, and the most common one is called leukoplakia.
Every dentist has heard of leukoplakia. That term is often misused because it means white patch, and a white patch can be attributed to any number of benign lesions and lesions with malignant potential. But it’s the ones with malignant potential classified as leukoplakia. If you have a patient with leukoplakia, there’s a risk, albeit relatively small, that over time, if left unchecked, it could eventually transform into cancer.
Chuck Cohen: One of the things I think you said that’s so true is the earlier we catch cancer in general, the earlier it’s caught, the easier it is to treat, and certainly the less dangerous it is for the patient. Then the other thing is, and I think we all know this, not only oral cancer too often leads to death, but even if the patient doesn’t die, the life changes that come from advanced-stage oral cancer are truly devastating.
Dr. Ross Kerr: Right. The estimates from the NCI and the American Cancer Society suggest that about 11,000 people die of oral and oropharyngeal cancer and pharyngeal cancer every year. And you’re right; there are thousands of oral and oropharynx cancer survivors. These patients, unfortunately, can have high morbidity because of the treatment for the disease.
The treatment for the disease can be disfiguring surgery that can impact the function of the head and neck area. It can also include radiation treatments that can have all kinds of complications: severe, dry mouth, fibrosis, where it’s difficult to open the mouth up, complications, dental complications because of the dry mouth and because of poor bone healing, and there are a whole host of different issues that these patients have to deal with for the rest of their lives. So, yes, it’s impactful. Obviously, if you catch it early, not only do you get a better survival, but the morbidity is reduced.
Chuck Cohen: Let’s talk a little bit about what dentists and dental professionals, like hygienists and assistants, can do to be better at finding oral cancers or potential or pre-cancers earlier and what they should do about it. If you could share your thoughts on that with us, that would be great.
Dr. Ross Kerr: Everyone has heard of screening for cancer and the concept of screening a general population. We don’t have population screening programs for oral cancer yet. Some countries have a higher burden of oral cancer, and we’re hoping that they will adopt formal screening programs. Taiwan is one of them, and it’s possible that will happen in India. But in the U.S., we rely on opportunistic screening by dentists, hygienists, and trained physicians, like ENTs.
The best screening technique is a visual and tactile examination. This is something that every dentist is trained to do. When any new patient, recall patient, or emergency patient comes in, they perform an examination to look for any lymph nodes. They assess whether or not the patient has any asymmetries looking at them.
And then they’ll go inside the mouth. They’ll not only examine the teeth and the gums, but they’ll also examine all of the mucosal structures. It takes just a couple of minutes. You pull down the lips, stick out the tongue, and look at every mucosal site. That’s how we detect any abnormal finding that deviates from what we would expect in a normal, healthy patient.
Chuck Cohen: And once we find something abnormal, then the next question is, what do we do next? So, there has to be some level of risk stratification. You have to go, “Is this something we need to be worried about, or is this something that is benign?” At the basic level, for people who aren’t interested in getting more education, at the very least, you make that decision about whether or not to refer to a qualified person. You take records and document what you’ve seen, then move that patient on to a specialist.
Dr. Ross Kerr: I would argue that dentists should be trained at a higher level because there aren’t many oral medicine specialists. I guess you could argue there are plenty of oral surgeons. There are plenty of oral pathologists and other people who have trained in this area. But I would argue that dentists can get trained beyond dental school to differentiate between something with malignant potential or something benign.
Chuck Cohen: Are there certain patients who are more likely to be candidates for oral cancer, or are there certain behaviors that make them more likely to be pre-cancerous or have lesions in their mouth that doctors should be more aware of?
Dr. Ross Kerr: Absolutely. In addition to performing a visual and tactile examination, it’s important to ask about the known risk factors for oral cancer and oral potentially malignant disorders. We know there’s very good epidemiologic evidence to support that tobacco of any form can cause cancer. But in the United States, most people smoke tobacco. There are parts of the U.S. where they chew tobacco.
In other parts of the world, they use it differently, and they use other products that have the potential to cause oral cancer. Depending on where you are in the United States, you may have ethnic groups, let’s say, from Southeast Asia, who chew the areca nut that’s often referred to as the betel nut. That’s another risk factor. So, there’s tobacco. Alcohol, too, particularly if you are a heavy alcohol user and combine it with tobacco products where the effect is multiplicative.
Then, poor diet is an established risk factor. There is some evidence to suggest that poor oral health may set things up as well. And then we haven’t broached this yet, but in the area of oropharynx cancer, there’s a very distinct risk factor, the HPV, which is the human papillomavirus. That, of course, is linked to sexual habits and exposure to that virus through sexual contact.
People who have multiple sexual encounters or practice oral sex may be at a heightened risk for developing the disease. Having said that, there are many patients that I have seen, and it’s a relatively small piece of the pie, who have absolutely no risk factors whatsoever. I have a group of women in their 30s who’ve come to see me with tongue cancer.
So, it’s not exclusively going to be discovered in patients who have these risk factors. Everyone must undergo a careful history and a careful visual and tactile examination.
Chuck Cohen: How can a doctor or dental professional do a visual examination of the areas behind the tongue? I mean, I’d imagine the farther you go back, the harder it is to see what’s going on, and you’re not going to stick your fingers down because you’d get a gag. What is the dentist due to test for to screen for that?
Dr. Ross Kerr: Right. Very good question. We do not have established screening parameters for oropharynx cancer, which is a sad state. I worked on a very preliminary feasibility study to do saliva detection of HPV, which may be a very crude way of screening people for HPV infection. The problem is that at any given moment, 1% of the population who submitted a mouth sample would be positive for HPV 16, which is the most common oncogenic subtype of HPV.
Well, clearly, if there are only 15,000 cases of HPV-positive oropharynx cancer in the United States each year, not everyone who gets infected with HPV develops cancer. It requires multiple exposures and other factors that cause a persistent infection. And slowly, over many years, ultimately, it transforms into cancer.
But to answer your question, it’s difficult to evaluate that part of the mouth. I will say that the most common presenting signs and symptoms of someone that has oropharynx cancer is a lump in their neck. More than 50% of patients present with a lump in their neck, which is essentially a lymph node involved, lead to further follow-up. Imaging will show that that patient has cancer in many cases, not in all.
The places HPV likes to grow and cause cancer are in the tonsillar tissues. Many people, including myself, had the palatine tonsil removed when they were young, but there were also tonsils at the backside of the tongue. When you stick your tongue all the way out where it dives back, that’s known as the base of the tongue, the posterior third of the tongue that contains lymphoid tonsil tissue. That’s one of the two places where oropharynx cancers can occur.
Sometimes, patients will experience changes in their swallowing ability or pain when swallowing, but not everyone. Some people will be completely asymptomatic in that area, but there’s a small cancer brewing. They just haven’t noticed it because it’s happened over a long time. We don’t have ways of screening this region yet.
Chuck Cohen: What are some tips that you might give to a general dentist or a hygienist about finding the right professional? Is it always the oral surgeon to be referring these cases to? Or are there others who might be the right candidate in a small town, let’s say, or even in a bigger town?
Dr. Ross Kerr: I think there are, I can’t remember how many oral surgeons there are in the United States, more than 10,000. Right? There are 250 oral medicine specialists. If you’re in a small town, you will either refer the patient to the physician or the oral surgeon. I think those would be the appropriate places to go. If you’re in a large center, you want to go to ideally an academic center.
I didn’t talk much about the signs and symptoms of what goes on with oral cavity cancers. I talked about the oropharynx, but oral cavity cancers can be a white patch, can be a red patch in the mouth, can be red and white patches, can be solitary ulceration, can be a small growth.
There are lots of things that can cause growth. There are lots of things that can cause ulcers in the mouth. There are lots of things that can cause red and white changes. So it’s these changes where the dentist or the hygienist looks at it and scratches their head. They say, “That doesn’t seem to be a canker sore” or “That doesn’t seem to be a traumatic type lesion of someone biting their tongue or cheek.” And so they’ve got to make that risk assessment.
But oral cancers and oral potentially malignant disorders have very variable presentations. Dentists have to realize that there is a spectrum of suspicious-looking changes in the mouth. If they’re not clear and their threshold is low, then they refer. If they’re a little bit more sophisticated because they’ve had extra training or taken an interest, the threshold is slightly higher.
Chuck Cohen: One of the things that you and I talked about for a few minutes before we started is the problem of false positives. I think there are a lot of dentists out there who find it easier to say nothing even when they think they may have found something than it is to refer the patient to the oral surgeon. Can you give us some ideas on how a general dentist should think about false positives?
Dr. Ross Kerr: Right. It is true that because there’s so much that goes on in the mouth, there are lots of reasons why someone can have a white area in their mouth. Most of the reasons for that are what we call frictional keratosis. In other words, it’s rubbing that area. Maybe something is rubbing a sharp tooth or rubbing against an area. It could be related to other habits they’re performing in the mouth.
And you’re right. Most of the lesions seen in the mouth will be largely benign, or if they have malignant potential, they have a relatively small chance of turning into a malignancy over time. There’s a very small group of lesions that are either early cancers or pre-cancers likely to turn into cancer.
The problem is there’s a lot of noise at the lower end. Cancers and high-grade lesions that aren’t cancers but are likely to turn into cancer are not likely to regress. Some do, but a very small fraction. Usually, they’re going to be persistent, and they’re going to be progressive.
One thing they can do is say to the patient, “Well, I think this may be because you’re rubbing your tongue or because your mouth is a little dry, you’re more prone to developing these little white patches. Let’s try and smooth off that tooth.” Then, bring the patient back after a couple of weeks or three weeks to see what happens. That’s one way you can have the patient come back and follow them. And if it’s still persistent, then you can move them on.
The other thing would be, wouldn’t it be great if we had some type of test that would allow us to do in the office very easily, give us immediate gratification, and risk-stratify using technology? The best technology out there is cytopathology, collecting cells with a brush. You collect those cells. For all of the platforms in the United States, currently, you have to send out those cells to a lab, and then they’ll give you the results a couple of weeks later. I think we need to develop tests that are real-time chairside, relatively inexpensive. We’re developing a platform like that at NYU.
I think that is sort of the future, maybe salivary diagnostics, maybe other blood tests. There are now blood tests, the gallery blood test that tests for 50 different cancers. You’ve got to pay quite a bit of money. Insurance companies aren’t necessarily going to cover that, but that does also cover the oral cavity and oropharynx. They’re not perfect but probably the way of the future.
The next thing I would say is dentists should go, and hygienists should get advanced training in this area. I’d be happy to help direct them toward the American Academy of Oral Medicine. We offer CE in that area, and other people do that. So that’s another way of getting more advanced training in this area. And it’s not just about oral cancer, but it’s an education about all of the other myriad of diseases that can occur in the mouth that are unrelated to the teeth and the gums.
It’s interesting because the mindset of physicians is very different from the mindset of dentists. Dentists seem concerned about telling patients that they need to be referred somewhere. They should drop that. Physicians don’t even think about it. They don’t think twice about referring patients to their colleagues when they don’t know what’s going on. They just feel more comfortable having that conversation with their patients.
That is a cultural change that needs to happen, and it needs to happen at the level of dental schools. It’s hard because most dentists don’t see many serious diseases. This is one of the few diseases that could have a major impact on their patients’ lives.
Finally, I would say that dentists struggle to pack everything into a day. If they are working with the hygienist, pass on this responsibility to the hygienist. Let the hygienist do the opportunistic screening. Train them to do that and then present the findings to the dentists. That might be a way of capturing more diseases.
Chuck Cohen: I love that. I want to summarize it because as we close, I want to make sure that everyone who watches this gets some take homes that they can take back to their practice. So the first thing I heard you say is get trained, so you know what you’re looking at. The second thing I heard you say is every patient should be examined, right? Every patient. Although certain patients have more activities and history, every patient should be screened and examined.
And then the third thing, which I thought was insightful, is everybody should get comfortable either in saying to the patient, “Why don’t you come back in three weeks, and let’s look at this again,” or “I want to send you to the oral surgeon.” Because I agree that part of the challenge for most dentists and hygienists is that they’re just not comfortable with that conversation. They’d rather say nothing than have a difficult conversation with the patient or the other dental professional, the oral surgeon.
That’s sort of the summary, right? Get trained, examine every patient thoroughly, and get comfortable with the topic to have a productive conversation with the patient and/or with a fellow dental professional or physician about what you see in the mouth.
Dr. Ross Kerr: Can I add just a couple of little points, please? Number one is that there are some fantastic resources available, and one of the best resources available is the Oral Cancer Foundation. They have, first of all, a tremendous support site for survivors of oral cancer. Tremendous education can be had just by reading through a number of different websites or web pages. So that’s Oral Cancer Foundation. Just Google that, and you’ll find a lot of great resources.
The other thing that I will say is we talked about oropharynx cancer, and what’s interesting is that there is a real spike in oropharynx cancers in the United States. The curve is sharply rising. It will eventually come down when all the population gets vaccinated. We do have an approved vaccination against oropharynx cancer. Kids from the age of 9 to the age of 26 are eligible for this vaccine. It will take care of almost all of the HPV subtypes.
There’s now a vaccine covering nine different strains, well, subtypes of HPV. Seven of which are cancer-causing. The statistics show a 3 to 1 ratio, men to women. The men who get it are largely in their 50s and 60s and are affluent. They’re just the types of patients coming to the general dentist.
So, it’s very important that the exam includes palpation of the neck lymph nodes and trying to promote the concept that this is something that we need to be concerned about and heighten awareness of this disease. That would be another piece that I would like to promote.
Chuck Cohen: Excellent. Dr. Kerr, thank you very much. Is there anything else you want to share as we close today’s podcast?
Dr. Ross Kerr: April is Oral Cancer Awareness Month. Take an opportunity to open up your offices for a free screening or whatever. And as I said, if you want to get some materials and read up, go to the Oral Cancer Foundation website. That’s it. Thank you so much for having me. I do appreciate it.
Chuck Cohen: Dr. Kerr, thank you very much for being here today. Our guest today was Dr. Ross Kerr, a professor at New York University Dental School and an oral medicine expert. Oral medicine. The trick term is you are a doctor of oral medicine, is that correct?
Dr. Ross Kerr: Oral medicine specialist.
Chuck Cohen: Thank you very much, Dr. Kerr. Great to have everyone here today. Go out and find some cancer in the mouth.