Mohs Surgery for Keratinocyte Carcinoma

In this interview, Dr Seaver Soon discussed his session, “Pro and Con: Contentious Concepts” at the 2023 ACMS Annual Meeting. He covered the topic, “Superficial Radiation vs Mohs for Keratinocyte Carcinoma: Pro Mohs.”

Seaver L. Soon, MD, is a dermatologist in San Diego, CA, and is affiliated with Scripps Green Hospital and Naval Medical Center San Diego.

The Dermatologist: Can you give us a recap of what was covered during your session at the 2023 ACMS Annual Meeting?

Dr Soon: At the ACMS 2023 Annual Meeting, I was involved in a contentious topic session that explored the data supporting the use of superficial radiation therapy and Mohs micrographic surgery for the treatment of low-risk keratinocyte carcinoma, specifically basal cell and squamous cell carcinoma.

The Dermatologist: Can you elaborate on the pros and cons of superficial radiation therapy and Mohs micrographic surgery for the management of keratinocyte carcinomas?

Dr Soon: This has been an interesting and contentious topic historically. The session was set up as a debate style where Dr Vladimir Ratushny and I explored the topics of superficial radiation therapy and Mohs micrographic surgery. He was charged with exploring the topic of superficial radiation therapy. And the main pro of superficial radiation therapy, which is the use of photon or light energy in the kilovolt range (50 to 150 kilovolts to treat superficial low-risk in cancers), is that it is relatively painless, and so it may be useful in that respect. It has good cure recurrence rates based on retrospective series in the range of 2% to 4% at about 5 years.

Dr Ratushny explored the proposed appropriate use criteria for superficial radiation therapy, meaning superficial radiation therapy should be used for low-risk skin cancers of the central face because of the risk of scarring and also that it could be used in patients who are on anticoagulants or in frail elderly patients. And the main pros of radiation therapy are that it is a painless procedure that theoretically produces very little scarring and can be completed in 6 to 12 weekly sessions.

I was charged with exploring the data supporting the use of Mohs surgery, which is the gold standard for treatment of skin cancers of the head and neck. And, obviously, the main benefits of Mohs surgery are its margin control and it has the highest cure rates of any treatment for skin cancer. The detractors are that there is a risk of scarring and in elderly patients it may be a lot to put them through a surgical procedure.

The Dermatologist: Can you go over the key points from the session in detail?

Dr Soon: The main points I explored during my presentation were that there are some problematic areas with the use of superficial radiation therapy. Specifically, not all low-risk skin cancers are truly low-risk skin cancers. In several pathology studies or histologic studies, it was demonstrated that about 15% of superficial basal cell carcinomas actually harbor an aggressive histology, so infiltrated basal cell carcinoma within the lesion if you step section through the biopsy site. And this is problematic because the reported cure rates for superficial radiation therapy actually decreased substantially when it is used to treat infiltrated basal cell carcinoma. Just because a tumor appears superficial on biopsy or low risk on biopsy, it may not actually be a low-risk tumor.

The second point covered was that even though superficial radiation therapy is purported to have a low risk of scarring, many patients actually do report atrophic depressed white scars with telangiectasias long term. Interestingly, when the Cochran analysis compared cosmetic outcomes of surgery vs radiation therapy at 4 years out, surgery was deemed to produce better cosmetic outcomes in randomized studies. Similarly with most surgery, there are lots of quality of life studies showing that patients are actually quite pleased with the surgical reconstruction achieved after no surgery.

And then, finally, there is a sense that elderly patients cannot tolerate surgery. This question was addressed in a multi-center Spanish study involving over 2000 patients called the REGEMOHS study, which demonstrated that older patients or patients older than 80 years old actually tolerated Mohs surgery as well as younger patients, and the outcomes were similar. So, this suggests that Mohs surgery is likely the better option for treatment of these tumors.

The Dermatologist: Are there any more insights you would like to share about superficial radiation therapy and Mohs micrographic surgery?

Dr Soon: I think the American Academy of Dermatology in their position statement, most recently revised in November 2021, summarizes it well. In this position statement, they state that surgical resection is the most efficient and effective way of treating basal cell and squamous cell carcinoma. They recommend the consideration of superficial radiation therapy when surgery is either contraindicated, if the patient refuses surgical treatment, or if the patient is not a candidate for surgery. And they recommend further research on superficial radiation therapy in the treatment of keratinocyte carcinoma, specifically looking at long-term outcomes, which is currently not available for superficial radiation therapy.

Reference
Soon S. Pro and con: contentious concepts. Presented at: American College of Mohs Surgery (ACMS) Annual Meeting; May 4–7, 2023; Seattle, WA.

Watch Dr Soon's video interview!