What is the role of sentinel lymph node biopsy for primary cSCC of the head and neck?
Clinical Applications
Dr. Schwarzenberger is the former physician editor of DermWorld. She interviews the author of a recent study each month.
By Kathryn Schwarzenberger, MD, FAAD, September 1, 2022
In this month’s Clinical Applications column, Physician Editor Kathryn Schwarzenberger, MD, FAAD, talks with Christian L. Baum, MD, FAAD, from the Mayo Clinic, about his Dermatologic Surgery paper, ‘Outcomes of Sentinel Lymph Node Biopsy for Primary Cutaneous Squamous Cell Carcinoma of the Head and Neck.’
DermWorld: You and your colleagues recently published a study from your institution on the outcomes of sentinel lymph node biopsy for head and neck squamous cell carcinomas. For those who may have not had a chance to read the article, can you briefly describe the study and your findings?
DermWorld: Most dermatologists are comfortable with indications for sentinel lymph node biopsy for melanoma. However, I’m not sure that is the case for squamous cell carcinoma. When do you recommend this be considered?
Dr. Baum: We don’t have sufficient data to support clear indications for SLNB in cSCC as we do with melanoma. Although the existing data suggest that BWH T2b may be a cohort with a sufficiently high risk of microscopic nodal disease to warrant additional study of SLNB, it is not clear whether a positive SLNB is associated with any difference in clinical outcomes. Presently, the National Comprehensive Cancer Network guidelines for squamous cell carcinoma recommend discussion and consideration of SLNB prior to excision for very high-risk tumors that are recurrent or have multiple risk factors and have a normal clinical nodal exam.
DermWorld: Does the site matter? Should we be considering SLNB for any higher risk SCC, or just those on head and neck? Or do we know yet?
Dr. Baum: Most of the literature regarding SLNB for cSCC involves the head and neck. We do not have sufficient data at the present time to stratify the utility of SLNB based upon anatomic location of the tumor.
DermWorld: Looking at the numbers, if 3-5% of patients with SCC will develop metastasis and there are over one million cases annually, we could expect to see between 30,000-50,000 cases of metastatic SCC each year. I suspect most dermatologists are not seeing these numbers in their own practices. Do you have any guesses who is caring for these patients?
Dr. Baum: There appears to be a discrepancy between the estimates of metastatic disease and reality. I suspect the rate is much lower than 3-5%. Even in a tertiary-referral center that is enriched with immunosuppressed patients such as Mayo Clinic, we’re not seeing numbers that reflect those estimates. A recent publication from our colleagues in the Netherlands reported a metastatic rate of 1.9% from their national registry (J Am Acad Dermatol. 2022;86(2):331-338). We need a robust national registry to get a better handle on the actual numbers.
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DermWorld: Is sentinel lymph node the best test for metastatic disease? Would we get the same information from any other studies, such as a PET-CT scan? Should we be ordering more of these?
Dr. Baum: We simply don’t know. This is a great question for a future study.
DermWorld: It seems like patients with higher-risk squamous cell carcinomas might benefit from a multispecialty team approach. Do you have any advice for dermatologists who are caring for these patients who might not work in such a setting?
Dr. Baum: Regardless of the exact role for SLNB in the management of high-risk cSCC, the role of a multi-disciplinary team cannot be over-emphasized. They need experts who know how to resect the tumors and reconstruct the surgical defects (which are not infrequently quite large and deep). They need experts who are familiar with interpreting radiologic imaging. They need experts who are familiar with managing immunosuppressive medications. They need experts who are familiar with delivering systemic therapy and radiation. If such expertise is not available, I would strongly recommend a referral to a center that is able to deliver multidisciplinary care.
Dr. Baum is professor of dermatology and vice chair of the Dermatology Department at the Mayo Clinic. His paper appeared in Dermatologic Surgery (doi:10.1097/DSS.0000000000003304). He does not have any relevant financial and/or commercial conflicts of interest to disclose.
Disclaimer: The views and opinions expressed in this article do not necessarily reflect those of DermWorld.
