What is Mohs surgery?
Mohs surgery is a precise surgical technique used to treat skin cancer. The procedure is named after Dr Frederick E. Mohs who developed this technique in 1938 to remove skin cancer lesions. Since its development, Mohs surgery has been refined into a precise and advanced treatment for skin cancer. Mohs surgery is so effective because 100 percent of the surgical margins are evaluated, compared with less than 5 percent by traditional techniques.
During Mohs surgery, the surgeon removes thin layers of skin one layer at a time and examines each layer under a microscope to determine if any cancer remains. This procedure continues until the tissue is cancer-free
The goal of this treatment is to minimize the chance of the cancer growing back, preserve as much healthy skin as possible and maximize the functional and cosmetic outcome.
Mohs surgery is an improvement to standard surgery (local excision), which involves removing the visible cancer with standard clear margins of surrounding healthy tissue all at once. In contrast, Mohs surgery allows the Mohs surgeon to verify that all cancer cells have been removed at the time of surgery. This increases the chance of a cure and reduces the need for additional treatments or additional surgery.
Why is Mohs surgery performed?
Mohs surgery is especially useful for skin cancers that:
- Have a high risk of recurrence or that have recurred after previous treatment
- Are located in areas where you want to preserve as much healthy tissue as possible, such as around the eyes, ears, nose, mouth, hands, feet and genitals
- Have borders that are hard to define
- Are large or aggressive
Mohs surgery procedure
The Mohs procedure takes place in the outpatient office setting. Mohs surgery is performed under local anaesthesia. This means the patient is awake during the procedure so that it can be safely performed in an outpatient office setting, without the need for general anaesthesia.
The surgeon starts by first excising out the visible skin cancer together with a thin layer of surrounding skin. The patient is then bandaged so that he/she can wait comfortably in a resting area. The excised tissue is processed by a Mohs technician, which will then be examined by the Mohs surgeon under the microscope. This will gauge the extent of the skin cancer and identify microscopic roots. If tumour cells remain at any of the margins, the map is used to remove an additional tissue layer precisely at the area where cancer remains. This procedure continues until the tissue is cancer-free and allows normal, healthy, surrounding tissue to be spared.
After the skin cancer has been removed by Mohs surgery, repairing the site of the skin cancer can often be performed by the Mohs surgeon or a reconstructive surgeon on the same day. The entire procedure usually lasts several hours.