Cutaneous Squamous Cell Carcinoma: Incidence and Risk Factors

Transcript:

Nikhil I. Khushalani, MD: Hello, and welcome to this OncLive Peer Exchange® titled “Data Updates in the Treatment of Resectable Cutaneous Squamous Cell Carcinoma.” I am Nikhil Khushalani. I’m a medical oncologist and senior member and vice chair in the department of cutaneous oncology at the Moffitt Cancer Center in Tampa, Florida. Today it is my distinct privilege and pleasure to be joined by a panel of experts in the management of cutaneous squamous cell carcinoma, and henceforth we’ll refer to this as “CSCC.” And I would like to welcome my fellow esteemed panel members to this discussion, and we’ll have them introduce themselves. We’ll start with Dr Dietrich.

Martin F. Dietrich, MD, PhD: Thank you for having me. My name is Martin Dietrich. I’m a medical oncologist at the University of Central Florida Cancer Center in Orlando, Florida. I have a Florida cancer specialist on my clinical arm.

Nikhil I. Khushalani, MD: Thank you for joining us. Dr Jason Luke.

Jason J. Luke, MD: Hello, I’m Jason Luke. I’m a medical oncologist focused on cutaneous oncology, as well as drug development for advanced cancers. I’m excited to participate today.

Nikhil I. Khushalani, MD: Thank you for joining us, and Dr Vishal Patel?

Vishal A. Patel, MD, FAAD, FACMS: Thank you, Dr Khushalani. Nice to be here with everybody. I am Vishal Patel. I’m a trained dermatologist and a Mohs surgeon. I focus my time on advanced skin cancer. I’m the director of cutaneous oncology at the GW [George Washington University] Cancer Center in Washington, DC, where I oversee some of their skin cancer immunotherapy programs.

Nikhil I. Khushalani, MD: Thank you again to our panel members for joining us, and as you can all see, this is truly a multidisciplinary effort that we hope to imbibe and share some of our experience, as well as expertise. Today we are going to discuss a number of recent updates in the treatment of resectable CSCC, with a specific emphasis on immunotherapy regimens that are being explored in the neoadjuvant setting. We’ll discuss the recent data, some of the recent publications, and their potential impact on clinical practice. And we’ve tried to divide this into several modules so that we start off with some of the high-risk features in cutaneous squamous cell carcinoma and directly dive into the data. I’d like to keep this conversational, informal, so that everyone can share their perspective. We’ll start with staging and risk factors for stratification of cutaneous squamous cell carcinoma. Dr Patel, how has the incidence of CSCC evolved and changed over time? What have you seen and what are your perspectives on this?

Vishal A. Patel, MD, FAAD, FACMS: We’ve seen a huge rise, an exponential rise in the incidence of CSCC. And the difficulty with nonmelanoma skin cancer, as compared to melanoma, as its counterpart, usually stratified and dichotomously between nonmelanoma and melanoma, we’ve always had great numbers with melanoma. It’s included in the SEER [Surveillance, Epidemiology, and End Results Program] database, and we look at both invasive and in situ melanomas. Keep track of those. And as a result of that, also keep track of deaths. This year, we think of melanomas as being on the downslope, as it relates to mortality, and we’ll be under 7000 deaths, and even falling from that, from the advent of immunotherapy. In contrast, cutaneous squamous cell carcinoma, the incidence is rising exponentially and has been for many years, but it’s not captured within this SEER database. A large reason for that is that there are so many low-risk cutaneous squamous cells, as well as in situ tumors that it would be impractical to capture all of these tumors. As a whole, between nonmelanoma skin cancers, the largest 2 tumors being basal cell carcinoma and squamous cell carcinoma, we traditionally have attributed this group as being 80% basal cell carcinoma, and 20% squamous cell carcinoma. In reality, we’re seeing that that nomenclature, that split, is not quite accurate. In fact, it may be closer to 50/50, so I’m going to say may be 60/40. Largely due to the aging population and how much of an increase in cutaneous squamous cell carcinoma we’re seeing, practically, in our clinical practices. It’s also the fact that immunosuppression is a big risk factor, and I’m sure we’ll talk about that later. A lot of our patients who have had transplants, or are having the advent of immunosuppressive diseases, now are developing cutaneous squamous cell carcinomas. And the last point I’ll say is, because we don’t keep track of these tumors, it’s difficult for us to say exactly how many patients die of squamous cell carcinoma, but we estimate that may be between 7000 up to 15,000. More recent estimates have put that above 10,000. And as a reference, as I said with melanoma, that would put that above the annual deaths for squamous cell carcinoma. It certainly is a disease process that we have begun to give more attention to, and rightfully so.

Nikhil I. Khushalani, MD: Thank you. That was very comprehensive. You’re right. We’re identifying more of these patients. We’re certainly in our medical oncology practice seeing more of these high-risk patients, and some of them are potentially even coming to us at an earlier stage. You did bring up the issue of immunosuppression. With the increasing number of solid organ transplants in the United States, we are seeing this has a definitive risk factor for the development of CSCC. And as you pointed out, patients who are solid organ transplant recipients probably have close to somewhere between an 80 to a 100-fold increase in their risk of CSCC, and that puts it as the more common cutaneous malignancy, relative to basal cell melanoma or Merkel cell, in that particular population. And those patients present unique challenges and absolutely benefit from multidisciplinary input into their care, as well.

Jason J. Luke, MD: Could I make a comment quick, to reinforce a couple things there, which is this issue of immunosuppression. And certainly, solid organ transplants are a major source of this, and it’s worth highlighting that, in fact, in the transplant population, the second highest risk of death across the transplant population, after obviously rejection of whatever graft they had, is death from cutaneous squamous cell carcinoma. Anywhere that there is a program for solid organ transplant, these patients need to be followed very closely for a long time. And a lot of these are latent, where you think you’re in a good shape because you haven’t rejected the graft 5 years, 10 years, and then you get out to year 12, year 15, and that’s when we start to see a lot of trouble with some of these continuous lesions. That’s when I wanted to highlight. I also wanted to put just a quick plug in for Medox to realize that patients with CLL, chronic lymphocytic leukemia, are also at high risk, especially now that we have this kick-the-can-down-the-road approach in CLL, where we’ve got a million active drugs that are going on forever and ever. The price does come due eventually, and oftentimes, unfortunately, that is in the context of continuous squam. Now, we’ll start talking about how to manage this a bit later, and what to do in that context of immunosuppression is complicated. But it’s worth realizing there’s a lot more of these patients out there than most people probably think about.

Transcript edited for clarity.