Dr. Monty Pal and Dr. Ari Rosenberg discuss the evolution of treatment strategies in head and neck cancers, including the challenges of treating both HPV-positive and HPV-negative disease and the emergence of blood-based biomarkers to advance personalized therapy across different subtypes.

TRANSCRIPT

Dr. Monty Pal: Hello and welcome to the ASCO Daily News Podcast. I'm your host, Dr. Monty Pal. I'm a medical oncologist, professor, and vice chair of academic affairs at the City of Hope Comprehensive Cancer Center in Los Angeles. Today, we're going to explore the evolving landscape of treatment strategies in head and neck cancer management, including locoregionally advanced head and neck squamous cell carcinoma, which happens to be on the rise in United States, in part due to spike in HPV-mediated oropharyngeal cancers.

We're also going to discuss the emerging strategies of using blood-based biomarkers to really advance personalized therapy. Joining me for this discussion is Dr. Ari Rosenberg. He's a medical oncologist focused on head and neck cancer, and he's an associate professor – congratulations on the recent promotion – at the University of Chicago. The University of Chicago has really produced luminaries in this field, Dr. Rosenberg included. I've had the pleasure of getting to know Dr. Ezra Cohen over the years, who really had his grounding there, and of course Everett Vokes, former ASCO President.

I'm really looking forward to this conversation, Ari. Thanks so much for joining us.

Dr. Ari Rosenberg: Thanks, Monty. Thanks for the invitation.

Dr. Monty Pal: You got it. And just a quick note for our listeners, our full disclosures are going to be in the transcript at the end of this episode. So let's start with the basics, if you don't mind. So, head and neck cancers are very diverse and they're challenging, right? In the sense that they're near vital organs, the treatments, you know, as we all saw during fellowship, if not now in clinical practice. They can really have such a major impact on vital organ function, speech, swallowing, et cetera. Can you just comment on head and neck cancers that are on the rise in the U.S.? I alluded to this briefly. Particularly, we've heard this in the context of colorectal cancer and so forth. Are you actually seeing younger adults being affected by this?

Dr. Ari Rosenberg: Yeah, thanks for that. The vast majority of head and neck cancers are head and neck squamous cell carcinomas, as I'm sure many of the listeners recall as well from fellowship or their current training. And as you alluded to, the organ function, long-term and functional quality of life outcomes are quite important, particularly in the context that these develop in high value real estate, parts of our head and neck area that we use for speaking, swallowing, all sorts of other essential functions as well. As you also alluded to, we think of this in two different particular subtypes of head and neck cancer. The historical head and neck cancer from 50, 60 years ago was almost exclusively related to carcinogen exposure, tobacco, alcohol use, and that subtype of carcinogen-induced head and neck cancer has been slowly declining. However, over the last now several decades, we've been seeing an increase in primary oropharyngeal squamous cell carcinoma, mostly tonsil, base of tongue. These are attributable to HPV, human papillomavirus exposure. And that's now the majority of the head and neck cancers that we tend to see in our clinic. As you also alluded to, these have very different prognoses as well. HPV-related head and neck cancer has a much more favorable prognosis where much of the interest has been in can we de-intensify to optimize long-term function?

But then the non-HPV-related head and neck cancer, or what we call HPV-negative head and neck cancer, continue to be very, very challenging. We only managed to cure about half of these folks, with many of these patients developing the current disease. These patients, in addition to being difficult to treat, also have major impacts both in terms of the treatments they undergo as well as their disease that can impact their function and quality of life. And you hinted at this a little bit, but we have been seeing an increase in younger patients with HPV-negative head and neck cancer as well, which is quite concerning. Younger patients, oftentimes never smokers, never drinkers, who are developing non-HPV-negative head and neck cancer. And that's been a little bit of a more recent trend that we've been seeing as well. So, definitely a lot of work to be done to optimize and improve outcomes across all of these different head and neck cancer subtypes.

Dr. Monty Pal: I mean, I'm just curious, you know, in the context of colorectal cancer, one of the things that we talk about is the potential role of the microbiome driving some of these young-onset cancers with, you know, perhaps there being an impact on, for instance, inflammation and the gut and what have you. Tell me about head and neck cancer. Is this anything known as to why younger patients might be getting diagnosed with non-HPV type cancers? It's odd to me.

Dr. Ari Rosenberg: Yeah, it's a great question. A lot of people are working on it. I think we folks have hypotheses, but it hasn't totally panned out exactly what's going on there. It does have a little bit more of a tendency towards women, whereas historically head and neck cancer is much more common in men than it is in women. But lots of people working on that, whether it's related to chronic inflammation, whether it's related to the microbiome. Whether it's related to dental exposure, dental work. So, a lot of folks trying to parse that out because I agree with you, it needs to be identified alongside improving treatment paradigms for these patients, the young ones and the older patients as well.

Dr. Monty Pal: Interesting, interesting. You know, one of the phenomena that was sort of coming around when I was in training 25 years ago was this role of sort of induction therapy for head and neck cancers. And of course, it's really come full circle now to include checkpoint inhibitors and so forth. Tell me a little bit about this and how you apply it, maybe in an HPV-mediated context, maybe in a non-HPV context.

Dr. Ari Rosenberg: Yeah, absolutely. Induction chemotherapy, as you alluded to, or neoadjuvant chemotherapy, depending on what the locoregional treatment approach is. Similar to other cancer types where systemic control early on has many potential advantages in this setting. Now, in head and neck cancer, even though induction chemotherapy is quite active in head and neck cancer, both HPV-positive and HPV-negative with pretty good response rates. A survival advantage for all comers with local regionally advanced disease remains unproven. There's been two randomized trials, both underpowered, but essentially did not show a survival advantage, showing that induction chemotherapy for all patients with locoregionally advanced and neck cancer can't be justified for a survival advantage.

That being said though, there remains a number of potential advantages of giving induction or neoadjuvant chemotherapy, of course, improving systemic control and debulking the disease early on has potential advantages, and predicting the responsiveness to subsequent radiation treatment. We know for some time in head and neck cancer that the percentage of shrinkage or the response to induction chemotherapy actually predicts outcome related to radiation as a dynamic biomarker where response can be used to select patients, for example, for de-escalated radiation has been an area of active investigation, active research. And it also remains a key opportunity to evaluate predictive biomarkers and understanding pre and post treatment to better understand the biology. I'll just add to your question that recently over this past year, we also saw phase 3 data for neoadjuvant immunotherapy for a subset of head and neck cancer that is surgically resectable. And so that's reintroducing the potential benefit in the immunotherapy era of incorporating immunotherapy in the neoadjuvant or the induction setting as part of the evolving treatment paradigm for these diseases.

Dr. Monty Pal: That's really interesting. And you kind of alluded to already several topics that I plan to hit on, you know, for instance, the role of immune checkpoint inhibitors, induction, chemotherapy, and so forth. And you started to touch on biomarkers. And of course, I think that's something near and dear to many of us in academic oncology. One thing that we've started talking a lot about in the context of colorectal cancer is circulating tumor DNA. How do you think this might fit in the context of head and neck cancer? Can you give us a flavor for that?

Dr. Ari Rosenberg: Yeah, absolutely. In head and neck cancer, the current landscape is most developed for circulating tumor DNA for HPV-related head and neck cancer. The advantage of HPV-related head neck cancer is that you have a distinctive HPV DNA that does tend to spill out into the peripheral blood and can be detected using various different blood-based assays. And because of that advantage as a tissue agnostic approach, it turns out that a number of HPV DNA plasma assays are actually quite sensitive and quite specific. And a number of them have indeed been commercialized. Of course, not only for detecting a baseline, but also grading responsiveness during treatment and probably mo...