PORTLAND, ORE. – In his nearly 2 decades of dermatology practice, Keith L. Duffy, MD, has seen his share of cases where Mohs surgery was misused or misappropriated.
, Salt Lake City, said at the annual meeting of the Pacific Dermatologic Association. “I want to protect our specialty. I see patients who have dozens of skin cancers. I want to emphasize the long game of management in those patients. You have to think about the tumors in terms of decades.”
In 2012, an ad hoc task force from the American Academy of Dermatology (AAD), the American College of Mohs Surgery, the American Society for Dermatologic Surgery Association, and the American Society for Mohs Surgery developed appropriate use criteria (AUC) for 270 scenarios for which Mohs micrographic surgery (MMS) is frequently considered. The task force used a 9-point scale to rate each indication, as follows:
- A score of 7 to 9: The use of MMS is appropriate for the specific indication and is generally considered acceptable.
- A score of 4 to 6: The use of MMS is uncertain for the specific indication, although its use may be appropriate and acceptable.
- A score of 1 to 3: The use of MMS is inappropriate for the specific indication and is generally not considered acceptable.
These ratings were translated into a free Mohs Surgery Appropriate Use Criteria App developed by the AAD.
Subsequently, Dr. Duffy and colleagues retrospectively examined the University of Utah’s adherence to the Mohs AUC over the course of 3 months. Their analysis, published in 2015, included 1,026 nonmelanoma skin cancers in 724 patients. Of the 1,026 cancers, 350 (34.1%) were treated with MMS. Of these, 339 (96.9%) were deemed appropriate based on the AUC guidelines, 4 (1.1%) were deemed uncertain, and 7 (2%) were deemed inappropriate.
There were also 611 skin cancers that were not treated with Mohs but met criteria for treatment with Mohs. “Most of these were AUC 7 tumors,” Dr. Duffy said. “When I see an AUC 7 tumor, I give high consideration for certain anatomic locations, especially the lower leg, scalp, eyelid, genitalia, ear, hands, and feet. I also think about the patient’s age, the number of skin cancers, and histological characteristics. Consider the long game in management and remember that skin cancer patients can make a near infinite amount of skin cancers, so be conservative when excising skin cancers to preserve precious skin.”
In his opinion, full thickness wounds requiring sutures should be avoided on the scalp and lower leg, if possible. “Most carcinomas in these locations are superficial and not aggressive in immunocompetent patients,” said Dr. Duffy, who said he has had one patient in 12 years who was not a transplant patient who had a metastatic squamous cell carcinoma on the lower leg. “Postop complications can be totally avoided. I don’t worry about these patients bleeding or [about] dehiscence. They can go back and play golf the next day, so you save valuable skin where the real estate is precious. This underscores a practice pearl: Incorporate the Mohs AUC and consideration of anatomic location when considering the most appropriate treatment of skin cancers.”
He also advises dermatologists to consider the histopathologic characteristics of the tumor when treating skin cancers to reduce complications and save tissue, so that patients can resume their lifestyle. “When you read the pathology report, really think about what the dermatopathologist saw under the microscope,” said Dr. Duffy, who is an investigator at the University of Utah’s Huntsman Cancer Institute. He said that he is able to review the slides for 90% of his own cases before surgery. “I’m lucky that way, but if you have any questions, your dermatopathologist should be on speed dial.”
Ultimately, he concluded, proper selection of a treatment modality for a specific tumor and patient rules the day. “Tumors should be thought about in the context of the patient and not as a single or isolated cancer,” he said.
Dr. Duffy reported having no relevant disclosures.