Multiple options available for dermatologists to approach high-risk basal cell carcinoma
CHICAGO — Dermatologists have multiple ways to approach high-risk basal cell carcinomas — not every case must be treated with Mohs micrographic surgery nor sent to a radiation oncologist, according to Marc Brown, MD, professor of dermatology and oncology director at University of Rochester Medical Center and president-elect of the American Society for Dermatologic Surgery.
Basal cell carcinoma (BCC) has doubled in the U.S. in the past 30 years with a disproportionate increase in women, especially younger women.
Low-risk BCCs are smaller, superficial or nodular with well-defined clinical margins and are usually not located on the head and neck, Brown said.
High-risk BCCs, which can be difficult to treat, include those with an aggressive growth histologic pattern, and they are recurrent, larger in size, on the mask area of the face, and on previous areas of radiation or present in patients who are immunosuppressed, Brown said.
“Histology is obviously very important for defining our high-risk BCC,” he said. “You have to know your dermatopathologist because they can use different terms for high risk.”
The following are all categorized as an aggressive growth pattern: sclerosing, infiltrating, morpheaform, desmoplastic, micronodular, basosquamous, keratotic and perineural invasion, he added.
Tumor size is another important indicator for risk.
On the trunk or extremities, a tumor greater than 2 cm is high risk. On the cheek, forehead, scalp or neck anything greater than 1 cm is defined as high risk, and on the mask area, anything greater than 6 mm.
Guidelines on the care of BCC were published in Journal of the American Academy of Dermatology in 2018 (Bichakjian C, et al. J Am Acad Dermatol. 2018;doi:10.1016/j.jaad.2017.10.006). Brown was part of the expert workgroup that included research from 188 articles to make up the guidelines.
“This is the one sentence that I always point out when I go through this,” he said. “In general, treatment of BCC is most effectively accomplished by surgical therapy, there are relatively few exemptions to this guiding principle.”
Mohs surgery is considered the gold standard for getting rid of the tumor and gives a high success rate, he added.
“What makes Mohs surgery unique is the surgeon serves as the pathologist. You have an on-site lab and very meticulous mapping,” Brown said. “It’s a great procedure for those of us who are obsessive-compulsive people.”
He added that the horizontal sectioning in theory should look at 100% of the tumor, which differentiates it from standard vertical mapping.
The procedure is longer than other excisions, it also comes with a higher cost and extra training is required to be able to perform Mohs.
Radiation can be utilized; however, multiple visits are often needed.
“We’re not talking about superficial radiation; we’re talking about traditional radiation for these high-risk cancers,” Brown said. “If you have increased fractionization, you do get better cosmesis. It’s probably the most expensive treatment and there can be skin irritation and breakdown as a result. ... Also, finding a radiation oncologist who knows what they’re doing is sometimes a challenge.”
As for systemic treatments, Brown likes Hedgehog pathway inhibitors.
“They are new to add to our available treatments. The mechanism of action makes great sense,” he said.
Brown said he is impressed by clinical trial results for locally advanced BCC, with significantly improved quality of life for patients.
Currently, the cure rate is unknown as well as to how long to treat a patient.
“I think [Hedgehog pathway inhibitors] might have the utility to shrink the tumor before surgery, but we are still working that out,” Brown said. “In some patients, like the elderly, it’s not necessary to cure but to control the BCC.
“The best offense is a good defense. So, never forget, try to prevent the cancers in the first place,” he said. – by Abigail Sutton
Brown M, et al. High-risk skin cancers. Presented at: American Society for Dermatologic Surgery Annual Meeting; Oct. 24-27, 2019; Chicago.
Disclosure: Brown reports no relevant financial disclosures.