TORS in the Multidisciplinary Care of Patients with Oropharyngeal Squamous Cell Carcinoma Guideline

Dr. Chris Holsinger shares the new guideline from ASCO on transoral robotic surgery (TORS) for patients with oropharyngeal squamous cell carcinoma. He reviews the evidence-based recommendations on baseline assessment, the role of TORS in HPV-positive and HPV-negative disease and in the salvage/recurrent setting, which patients are eligible or ineligible for TORS, and the role of adjuvant therapy. He discusses the importance of multidisciplinary collaboration and shared decision-making between patients and their clinicians.

Read the full guideline, "Transoral Robotic Surgery in the Multidisciplinary Care of Patients with Oropharyngeal Squamous Cell Carcinoma: ASCO Guideline."

TRANSCRIPT

This guideline, clinical tools, and resources are available at asco.org. Read the full text of the guideline and review authors' disclosures of potential conflicts of interest in the Journal of Clinical Oncology.

Brittany Harvey: Hello and welcome to the ASCO Guidelines podcast, one of ASCO's podcasts, delivering timely information to keep you up to date on the latest changes, challenges and advances in oncology. You can find all the shows, including this one at asco.org/podcasts.

My name is Brittany Harvey and today I'm interviewing Dr. Chris Holsinger from Stanford University, lead author on "Transoral Robotic Surgery in the Multidisciplinary Care of Patients with Oropharyngeal Squamous Cell Carcinoma: ASCO Guideline."

Thank you for being here today, Dr. Holsinger.

Dr. Chris Holsinger: Thanks, Brittany. We've been working together for years on these guidelines and what a pleasure to get to meet you at least virtually today.

Brittany Harvey: Yes, it's great to have you on. And then just before we discuss this guideline, I'd like to note that ASCO takes great care in the development of its guidelines and ensuring that the ASCO conflict of interest policy is followed for each guideline. The disclosures of potential conflicts of interest for the guideline panel, including Dr. Holsinger, who has joined us here today, are available online with the publication of the guideline in the Journal of Clinical Oncology, which is linked in the show notes.

So let's jump into this important guideline. Dr. Holsinger, to start us off, can you provide an overview of both the scope and purpose of this guideline?

Dr. Chris Holsinger: Absolutely. And again, thanks for the opportunity to be here, Brittany. I appreciate the invitation to participate in the ASCO Guidelines and to work with the great people on this paper that's now out there.

I think it's a really important guideline to be published because it really talks about surgery, specifically transoral robotic surgery, a minimally invasive technique, as a new way to treat head and neck cancer. Why that's so important is that what is now known as head and neck cancer is completely different than what we saw even 25 years ago. Around the turn of the century, some really thoughtful epidemiologists working at Hopkins and UW in Seattle started to see this connection between the human papillomavirus and head and neck cancer. And since then we've seen this precipitous rise in the number of throat cancers specifically due to HPV. The results from the American Cancer Society showed last year that head neck cancer, in particular these cancers of the oropharynx, actually were one of the few cancers that still had an increasing incidence, I think it was around 2.5% per year. And other studies have shown that almost 50% of the cases we're seeing across the United States now are actually HPV-mediated throat cancers. That's bad news because we're seeing this rise in cases, but it's good news in the sense that this is a cancer that is highly curable and I think opens up a lot of different treatment avenues that we didn't have a couple of decades ago. And when patients are facing a mortality risk that's two or three times lower than the formerly HPV-negative smoking-driven cancers, it really behooves us as clinicians, as oncologists to think about treatment selection in a completely different way. And for years, the only function-sparing option, surgery certainly was not, was radiation therapy with concurrent cisplatin chemotherapy.

In 2009, the FDA approved the use of surgical robotics using a transoral approach, a minimally invasive approach to resect the primary tumors and to perform neck dissection. And so now when patients walk in the door, they not only have this gold standard option in the path of radiation therapy with chemo, but also frontline surgery. And with some recent publications, especially the ECOG 3311 study, there's some really good evidence that for HPV-mediated throat cancers, we can actually de-escalate the intensity of adjuvant therapy when we start with surgery first. So who we choose that option for, which patients want that option - these are all really important new questions that we try to grapple with in these guidelines.

Brittany Harvey: That background is really key for setting the stage for what we're about to talk about today.

And so next I'd like to review the key recommendations across the clinical questions that the panel addressed. So you just talked about the importance of treatment selection. So to start that off, first, what is recommended for baseline assessment for patients with oropharyngeal squamous cell carcinoma who are being considered for transoral robotic surgery?

Dr. Chris Holsinger: So I think here we tried in the guidelines to really standardize the workup and approach of this disease, in general, but with a strong focus on who might be a good surgical candidate. As I mentioned in the introduction, I mean, this is a disease that is very new. Our workup is in flux. And so what we tried to do, especially in items 1.2 and 1.3, is to really standardize and confirm that the tumor that we're dealing with, which oftentimes presents in a metastatic lymph node, is in fact associated with the human papillomavirus. So how biopsy is done, how high risk HPV testing is performed, whether you're doing that with an in situ hybridization, a DNA based study, or a p16 immunohistochemical study. And we try to tackle these issues first to really make sure that the patient population we're considering is actually indeed eligible for this kind of treatment de-escalation with surgery.

Brittany Harvey: Understood. So it's important to consider which patients could be eligible for TORS upfront.

So what is the role of TORS in patients with HPV-positive oropharyngeal squamous cell carcinoma?

Dr. Chris Holsinger: Yeah, exactly. So I think first of all, surgery is ideally suited, and the robot is FDA approved for early-stage cancers - T1 and T2 cancers that are amenable to a minimally invasive approach. And we really try to emphasize, especially in our patient selection section of the guideline, who is really an ideal candidate for this. It's not just the T1 and T2 tumor. It's a tumor that is lateralized so that we can maybe consider managing the neck concurrently just on the side of the tumor, rather than doing bilateral neck dissection for most patients. Which patients might get the best functional outcome is a really critical component of this. And in fact, that actually goes back to a guideline that we didn't have time to chat about earlier, which is that we think every head neck cancer patient, whether or not they're being considered for transoral robotic surgery or frontline radiation therapy with cisplatin, every patient should have a pre-treatment assessment by a speech and swallowing expert. They're called different names across the country: speech language pathologists, speech pathologists, etc. But having a really good functional assessment of the patient's ability to swallow before treatment selection is really critical. And why that's important with frontline surgery is that there's a period of about one or two weeks after which that patient really needs intensive rehabilitation. And so for every patient being considered by TORS, we want to work really hand in hand with that speech pathologist to do pre-habilitation and then immediate post-operative rehab and then long longitudinal rehabilitation so that if radiation is needed down the road in a month, that patient just hopefully sails through this de-escalated treatment that we're offering.

Brittany Harvey: Great. I appreciate you describing which patients can be considered for transoral robotic surgery.

So beyond that, which patients with HPV-positive oropharyngeal squamous cell carcinoma aren't really good candidates for TORS?

Dr. Chris Holsinger: We talked about that sort of ideal patient, but you know, we're not always living in an ideal world. And so I think it's important, and I'm really happy about the multidisciplinary discussions that led to these final guidelines because I think it helped engage radiation oncologists, medical oncologists, and surgeons around who's maybe not a good candidate for this because radiation therapy, with or without cisplatin chemotherapy, remains a good option for many of these patients. But I think the consensus, especially among the surgeons in this group, were that patients with tumors were more endophytic - that's the old fashioned oncology and surgical oncology term that refers to tumors that seem to not be as evident on the surface and have more of an infiltrative deep growth pattern - these are not ideal tumors. Whereas an exophytic tumor that's growing upwards, that's more readily seen on flexible endoscopy during a routine clinic assessment, or frankly, better seen on imaging, those exophytic tumors are better suited to a surgical approach because the surgeon has a better chance when he or she sees the tumor to get a good margin. When we can appreciate not just the surface mucosal margins that need to be taken, but also have a better chance to appreciate their depth. And with those infiltrative tumors, it's much harder to really understand how to get that deep margin, which in many cases is always the hardest. And so that's a long way to say that surgical decision making, patient selection is really critical when it comes to offering TORS as a multidisciplinary group.

And then there are a few other things that we can quickly talk about before we move on to discussing adjuvant therapy. But I think there are some relative contraindications to patients who might have tumors arising in a palatine tonsil or tonsillar pillar, but which might grow significantly into the soft palate, such that a major palatal resection would be needed to get a good margin. For T1 and T2 tumors, we're not sure that that is an ideal candidate. And the other relative contraindication, but it's a hard and fast contraindication in my personal practice, is patients with extensive nodal disease. I think a patient who has preoperative extranodal extension, matted nodes, clinically and on MRI, you know pre-op they're going to need intensive post operative concurrent chemoradiation post-op that's maybe not the best patient for TORS, although there are some select cases where that that might make sense. But that's a quick overview of patient selection for TORS, Brittany. Hopefully, that's helpful.

Brittany Harvey: That's definitely helpful. I think it's really important to consider not only who is eligible, but who isn't eligible for this de-escalation of treatment, and I appreciate you clarifying some of that.

So then you've just also mentioned adjuvant therapy along with multidisciplinary discussion. So what is recommended regarding adjuvant therapy for patients who have resected HPV-positive oropharyngeal squamous cell carcinoma?

Dr. Chris Holsinger: Definitely. And I think the post-operative discussion has to begin with great pre-op planning. And pre-op planning is really anchored in a really robust multidisciplinary team. So, we spoke earlier about the critical importance of getting speech language pathology involved initially, but they're part of a much larger team that includes not just a surgeon, but medical oncologist, a radiation oncologist and a dental oncologist - all of these specialties, and I could think of several others if we had time to chat further - this should also be really engaged in the care of these patients. But great decision making regarding adjuvant therapy really begins with a robust multidisciplinary consultation pre-op and we try to emphasize that in the guidelines.

But just to return and answer your question very directly, I think adjuvant therapy is really the critical piece in getting that great functional outcome for a patient with HPV-mediated throat cancer. And I think traditionally patients who have a variety of different risks, based on a large study done again by the ECOG group, ECOG 3311, we showed that by stratifying patients based on their surgical pathology rather than on an estimate of disease extent, we can better stratify adjuvant therapy. And so the low risk patient is a patient with good margins and of course, good margin, we could spend another two hours discussing that. But good margins are greater than at least 1 to 3 millimeters superficially and a clear deep margin. Patients with lymph node metastases that are less than 3 cm and a single lymph node can sometimes be observed but most patients don't fall into that low risk category. Most patients fall into an intermediate risk where the margin is good and it's clear, but it might be close. That depends if you're talking about the superficial mucosal margin or the deep. But more often than not, we spend a lot of time considering the extent of lymph node involvement as it pertains to how adjuvant therapy is delivered.

And I think for patients with less than 4 lymph nodes traditionally without extranodal extension, radiation therapy will suffice for adjuvant therapy after TORS. And the question of dose then comes up. Are we talking 50 Gray, the experimental arm that showed real promise in the ECOG 3311 trial, or 60 Gray or more traditional dose? And that is a topic definitely for another podcast, which we should do with a radiation oncologist online. I don't want to get into the weeds with that, but I refer you to our guidelines and Bob Ferris and Barbara Burtness' paper from JCO in 2021 for further details about that.

But then for patients with positive margins with more than four lymph nodes, but especially patients with extranodal extension, the role of radiation therapy and chemotherapy is really absolutely critical. Because these patients and while they only accounted for around 20% to 30% of patients that we're seeing in this new era of TORS, they're the ones that we're really focusing on how can we do better because their overall survival is still good, it's 90%, but it's not as good as the patients we're seeing with a low and intermediate risk. So that's a brief overview there.

Brittany Harvey: I appreciate that overview. And yes, we'll refer listeners to the full guideline, which is linked in the show notes of this episode to learn more about the intricacies of the radiation therapy that you mentioned.

So then we've talked a lot about patients with HPV-positive disease, but what is the role of TORS in patients with HPV-negative disease?

Dr. Chris Holsinger: I think TORS still has a role for these patients. Our colleague in India, Surender Dabas, has a really nice series that shows that for HPV-negative patients, this is a way for early stage cancers to potentially escalate the intensity of treatment for a disease that does worse than this new HPV-positive we're seeing in the US. So I think there's a good signal there. I think more study needs to be done and I think those studies, in fact, are underway in India and other countries. I hope that we can, as an oncology community here in the United States, also tackle this disease, which is still a significant part of the disease we face in head and neck oncology.

Brittany Harvey: Yes, we'll look forward to more data coming out for HPV-negative disease.

So then, the last clinical question that the guideline panel addressed: What is the role of TORS in the salvage or recurrent setting?

Dr. Chris Holsinger: So we wrap up the guidelines tackling this topic. It's definitely something for the experienced TORS surgeon in consultation with that multidisciplinary team. Oftentimes, we are still seeing many patients who need salvage surgery and I think, while TORS alone could be a really effective treatment option, TORS with a microvascular reconstruction is oftentimes what is needed for these patients who, with recurrence, do often present with an RT 2, 3, 4 tumor.

In my own practice, I found that using TORS as a way to minimize the superficial mucosal extent and then delivering that tumor through a traditional lateral pharyngotomy, then neck dissection and then having a microvascular flap inset done after that really provides the best possible chance for good long term function and of course control of the tumor. Here, I definitely refer the listener to some great work done out of the Royal Marsden with Vin Paleri, who we're happy to have on our TORS guideline panel for his RECUT study that really grapples in some detail with these very issues.

Brittany Harvey: Excellent. And so we've covered a lot of the recommendations here that were made by the panel and you've touched a little bit about how this changes things for clinicians in practice. But what should clinicians know as they implement these new recommendations?

Dr. Chris Holsinger: One thing as we close, I hope that in the future we can really start to grapple with this concept of patient selection. I think these guidelines help establish that TORS is a great oncologic option with - really the only option for treatment de-escalation in the here and now. Radiation therapy and cisplatin concurrent chemotherapy is going to be an option that is such an important choice for patients. And I think where I hope the field goes in the future is figuring out which patient wants one of these options. And I think certain patients really want that tumor taken out and others just the idea of surgery is not something that makes sense for them. How we in the context of a multidisciplinary team, really engage that patient, elicit their treatment preferences and then through considering treatment eligibility criteria that we've spelled out here for surgery and can be spelled out for chemo RT, bringing all that together in a formal shared decision making process is really where I hope the field will be going in the next few years. And hopefully these guidelines help to pave the way there.

Brittany Harvey: Definitely the aspect of care by a multidisciplinary team and talking with patients to go through shared decision making is key to implementing these guidelines. So then, in that same vein, what do these recommendations mean for patients with oropharyngeal squamous cell carcinoma?

Dr. Chris Holsinger: I think the central take home message for patients should be that especially if you have a T1 and T2 tumor, it's really important to have that consultation with a surgeon who knows how to do TORS and has a busy practice, but then also having an honest discussion up front about what the functional outcomes would be both with surgery and also chemo RT. And I think just knowing all those different options, that multidisciplinary treatment selection process is going to be that much more robust. And I think more right decisions will get made and we'll see less decisional regret down the road, which I think is a long term goal of our field.

Brittany Harvey: Absolutely. That discussion of preferences is key.

So then to wrap us up, you touched on this a little bit earlier in talking about ongoing research and data, particularly in the field of HPV-negative disease, but what are the outstanding questions regarding TORS in this patient population?

Dr. Chris Holsinger: Yeah, I think that in addition to this work around shared decision making, I really hope that we'll embrace shared decision making in the context of future clinical trial. I think where we are now is you have surgeons saying, "Hey, TORS and 50 gray is a great option. Why aren't we doing that?" And then our colleagues, perhaps across the aisle, if I can use a political metaphor, are saying, "Well, where's the comparative data? Can we even do a randomized clinical trial between surgery and radiation?" Well, Christian Simon in Lausanne in Switzerland is trying to do this in a small pilot study being led by the EORTC, and I would encourage American investigators to consider something analogous. But I think how we solve this question of I think treatment choice is going to be pivotal for any such trial to ever be done.

And then finally, I think, how will the changing treatment landscape around immunotherapy change this? There's some really provocative data that dates back to 1996 in a JCO paper from Ollivier Laccourreye and the University of Paris experience that showed induction chemotherapy followed by function preserving surgery in the larynx was a really powerful strategy for organ preservation, and that has never been followed up in the United States. And so especially with the upcoming presentation of KEYNOTE-689, will we be doing neoadjuvant approaches for patients and then following them by minimally invasive surgery or lower dose radiation? I think these are going to be some exciting new areas of study and I can't wait to see how this might evolve so we can refine the treatment - still get those great outcomes, but reduce those late toxicity.

Brittany Harvey: Yes. We'll look forward to this ongoing research to continue to move the field forward.

So, Dr. Holsinger, I want to thank you so much for your time to develop this important guideline. It's been great to have you on the podcast to discuss it today.

Dr. Chris Holsinger: Well, thanks a lot Brittany. It's nice to finally meet you.

Brittany Harvey: Likewise.

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