Mohs micrographic surgery is a surgical technique that’s used to treat melanoma skin cancer. It was developed to preserve as much healthy tissue as possible so any resulting scarring can be minimized. Mohs uses immediate lab evaluation of excised (removed) tissue to determine if all cancer cells have been removed from an area or if additional tissue needs to be removed to eliminate remaining cells. Developed in the 1930s, today Mohs surgery is used throughout the world to remove cancerous lesions, and because of its high degree of precision and the use of immediate lab analysis, it’s associated with extremely high cure rates.
Prior to the procedure, the treatment area will be thoroughly cleansed and a drape may be used to isolate it from the surrounding tissue. A local anesthetic will be injected around the treatment area to thoroughly numb it. No general anesthesia is required. Once the lesion is removed, it’s immediately evaluated under a microscope to determine if the edges or margins of the excised tissue are clear of cancer cells. If the margins are free of cancerous tissue, that’s an indication that all of the cancer cells have been removed, and the surgical site can be closed with sutures. When cancer cells are present on one or more margins, additional tissue will be removed in those areas and that tissue will be re-evaluated. The process of excision followed by microscopic evaluation continues until all margins are clear, at which point the incision site will be closed using very small sutures and a dressing will be applied. Mohs surgery can be performed as an outpatient procedure and patients will be discharged soon after their procedure is completed.
Many skin cancers can be much more extensive than they may appear on the surface, extending well below the skin and throughout muscles, blood vessels and other tissues and structures. Mohs surgery is designed to identify these areas of cancerous tissue that can be “missed” with traditional surgery techniques to help patients achieve far higher cure rates while also minimizing scarring and disfigurement.