QUEBEC CITY A quasi-Mohs micrographic surgery procedure involving excision and curettage with pathologic analysis of margins may be a practical way of treating skin cancer patients in areas that do not have access to Mohs surgeons, Louis Weatherhead, M.B., said at the annual conference of the Canadian Dermatology Association.
"In many areas in Canada, we do not have access to Mohs surgery," said Dr. Weatherhead, director of surgical dermatology at the University of Ottawa.
"Many plastic surgeons in the Ottawa region will not deal with a skin malignancy," he said.
The alternative to Mohs surgery, which Dr. Weatherhead teaches to his residents in Ottawa, is easy to learn and provides "clinically good results in clearance of tumor as well as postoperative appearance," he said.
The "poor man's Mohs procedure" has had a recurrence rate of about 2%4% over a 5-year period, he said. The relatively simple technique involves simple shaving and curettage plus excision, which most dermatologists know how to do, Dr. Weatherhead said in an interview.
At the dermatology clinic at the Ottawa Hospital, Dr. Weatherhead has not had positive margins in any patient who has undergone the procedure.
"In my hands it's been a very good tool, but there's always risk, when you do any surgical procedure, that you might have a margin that's still involved," he said, "in which case, then, many times in [basal cell carcinomas] you have to determine the amount of involvement and whether or not you're going to go back and do surgery or just observe, because in many instances the healing gets rid of residual tumor."
The first step of the procedure is "like doing your first Mohs cut," Dr. Weatherhead said, because it involves tangentially excising the lesion and submitting the specimen for pathologicbut not immediateanalysis. But the similarity between the procedure and Mohs stops there, because "we don't have the facility to continue it."
Curettage is performed to remove any residual tumor up to normal tissue and to delineate the borders of the tumor. Following hemostasis of the wound, Dr. Weatherhead excises a surgical margin of about 34 mm. The specimen obtained from that excision is then sent for pathologic analysis of the margin. The dermatologist chooses a method to close the wound depending on the location and size of the defect.
Skin cancer patient undergoing a quasi-Mohs procedure. From left to right: malignant lesion is excised; curettage ensures clear margins; a rotational flap closes wound.
Rotational flap is sutured in place (left). Good healing of the wound is seen after 1 week (right).
Final cosmetic result seen 1 year after having a quasi-Mohs micrographic surgery procedure. Photos courtesy Dr. Louis Weatherhead