Image-Guided SRT for Nonmelanoma Skin Cancer
Clinical Summary
Image-Guided Superficial Radiation Therapy for Nonmelanoma Skin Cancer
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Image-guided superficial radiation therapy (SRT), nonmelanoma skin cancer: Addition of high-resolution ultrasound guidance has improved treatment precision, producing cure rates “pretty darn close” to Mohs micrographic surgery while offering a non-surgical, non-painful, and non-scarring option.
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Patient selection: Ideal candidates include older patients with lesions on the lower legs or scalp and younger patients with tumors in cosmetically sensitive locations such as the nose, eyelid, or ear. Image-guided SRT is generally intended for nodular or superficial basal cell carcinoma and non-aggressive squamous cell carcinoma.
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Practical considerations: Less suitable for infiltrative basal cell carcinoma, recurrent tumors, or lesions within scars. A typical regimen may involve fractionated treatment delivered twice weekly for 7 weeks (14 total sessions), requiring multiple office visits.
Reviewed by Jessica Garlewicz, Managing Digital Editor of Immunology Group
Dr David Goldberg discusses how high-resolution ultrasound guidance is improving superficial radiation therapy for nonmelanoma skin cancers. Learn which patients and tumor types may benefit most from image-guided SRT, including older patients, poor surgical candidates, and those with lesions in cosmetically sensitive areas such as the nose, eyelid, ear, scalp, or lower legs.
Transcript
I'm Dr David Goldberg. I am the director of Clinical Research and Cosmetic Dermatology for the national private equity-based dermatology group, Schweiger Dermatology Group. I am also a clinical professor of dermatology at the Icahn School of Medicine at Mount Sinai in New York.
How has the integration of image guidance, such as high-resolution ultrasound, changed the role of superficial radiation therapy in managing nonmelanoma skin cancers?
Dr Goldberg: So superficial radiation therapy for the treatment of nonmelanoma skin cancer is actually not new. It was very popular in the 1970s, in the early 1980s, and then it kind of disappeared as Mohs micrographic surgery took over in the treatment of nonmelanoma skin cancer. Some maybe 15 years ago, this came back to the market as superficial radiation therapy as an alternative to surgery for those people who don't want surgery, maybe less scarring. But the cure rates were not quite as high as we see with Mohs surgery. Now that we've added image-guided ultrasound evaluation prior to the use of superficial radiation therapy, for many nonmelanoma skin cancers, we get cure rates that are pretty darn close to that of Mohs micrographic surgery. So for patients who are willing to come in for a series of visits because it is that. It's a non-surgical, non-painful, non-scarring approach and has really become very popular.
In which patient populations or anatomic locations do you see image-guided SRT offering the greatest advantage compared to traditional surgical approaches like Mohs?
Dr Goldberg: So image-guided SRT really comes into two different population bases. One is some older people who are not good surgical candidates. Classic examples are people maybe with skin cancers on their lower legs, where you don't want to do surgery because they're not going to heal so well, or maybe big areas on their scalp. That's the typical older patient. but more and more we're seeing some younger patients as well with nonmelanoma skin cancer where they might have it on their nose, on their eyelid, their ear, where they really don't want to lose that part of their body. A classic example I give, and I gave it during my lecture, was about five years ago I saw in my Manhattan office an attorney, and she came to the office, and she said to me, Dr Goldberg, I know you're a Mohs surgeon and I know you're an attorney, she said, I want to tell you that I sue doctors all the time. But I don't want Mohs surgery for the skin cancer on my nose. I want you to do radiation therapy. And you might tell me the cure rate's not as high, which then it wasn't. It is now with image-guided SRT. She said, but I want it anyway because I don't want to lose part of my nose. So older people: lower leg, scalp. Younger people: their nose, their ear, their eyelid, cosmetically sensitive areas.
What practical considerations should dermatologists keep in mind when selecting patients for SRT to optimize both oncologic outcomes and cosmetic results?
Dr Goldberg: So there are skin cancers that are optimal for superficial radiation therapy, and there are those that are not. Some of the more difficult nonmelanoma skin cancers, such as infiltrative basal cell carcinoma, perhaps recurrent lesions, lesions that are present in scars, those are not ideal for superficial radiation therapy. It's really meant for the very common, we call them nodular, or superficial basal cell carcinoma, or non-aggressive squamous cell carcinoma. Those people are ideal for this. Now, the flip side is, and everybody does this a little bit differently, but you take a dosage of the radiation therapy, let's call it a thousand-watt light bulb, and you fractionate that. You don't do it all at one time because you want them to heal nicely. And so that thousand watts, if you will, is then divided into two sessions a week for seven weeks. So some people do more sessions than that. We do 14 total. The negative is they have to come in for a lot of visits. The positive is it's like going to the dentist, having the lead drape put on you, and instead of that thing being put in your mouth, it's put on your skin cancer.
