Mohs Micrographic Surgery

Skin cancers are the most common group of cancers in the UK with around 60,000 new cases in England and Wales each year. They make up 20% of all cancer registrations. The total number of skin cancers has more than doubled in 10 years. Three types (basal cell carcinoma (BCC), squamous cell carcinoma (SCC) and malignant melanoma) make up more than 95% of all skin cancers. BCC and SCCs are grouped together as non-melanoma skin cancer (NMSC). Many patients will have more than one skin cancer. The type of treatment given depends on many factors including the site, type and extent of tumour. Options include surgery, radiotherapy and topical therapy with creams.

Some skin cancers can be deceptively large and more extensive under the skin than they appear to be from the surface. They may have “roots” in the skin, or along blood vessels, nerves, or cartilage. Skin cancers that have recurred after previous treatment may have extensions deep under the scar that has formed at the site. Conventional treatment with surgery or radiotherapy can often miss these roots leading to recurrences, which can be more aggressive than the original tumour.

Mohs micrographic surgery

Mohs micrographic surgery is a specialized, highly effective technique specifically designed to remove these cancers. It differs from other skin cancer treatments in that it permits the immediate and complete microscopic examination of cancerous tissue, so that all its extensions can be eliminated. It has been recognized as the skin cancer treatment with the highest reported cure rate whilst conserving as much normal skin as possible. It was developed in the 1930s by Dr. Frederic Mohs at the University of Wisconsin and is now practiced in specialist centres throughout the world. The surgery is performed as an outpatient procedure. Although the patient is usually awake during the entire procedure, discomfort is often no greater than it would be for more routine skin cancer surgeries.

It is important to note that Mohs surgery is not appropriate for all skin cancers. It is typically is reserved for cancers located in areas such as the face, hands, feet, and genitals, where maximal preservation of healthy tissue is critical for cosmetic or functional purposes, or for cancers that have recurred following previous treatment.

It is impossible to predict precisely how much skin will have to be removed. The final surgical defect could be only slightly larger than the initial skin cancer, but occasionally the removal of the deep extensions results in a larger defect. However the patient should keep in mind that Mohs surgery only removes only the cancerous tissue, while the normal tissue is spared.

Special Qualifications of the Mohs Surgeon

The vast majority of physicians performing Mohs surgery are dermatologists. They should also have specialized skills in dermatological surgery and dermatopathology. Ideally they should have completed a one year full-time intensive fellowship in Mohs surgery following their dermatology training. Some surgeons claim to be carrying out the Mohs procedure because they are doing “frozen-section histopathology”, but this is not the same thing as process is quite different and does not have the same degree of accuracy.

The Mohs surgeons at Cedars are fellowship-trained.