Mohs Surgery

Mohs surgery is technique for the microscopically- controlled excision of skin cancer, produces the highest cure rate for non-melanoma skin cancers suitable for the procedure. The technique combines surgical removal of the skin cancer in a precise layer-by layer removal, with immediate microscopic examination of the removed tissue, using horizontal frozen sections to ensure no tumour remains.

Once clearance is achieved, the wound can be repaired. This process should not be confused with frozen sections, which refers to random, intermittent sectioning, examining only a small area of the overall specimen. Skin cancer is by far the most common malignant tumour in humans. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma. 

Both basal cell carcinoma and squamous cell carcinoma begin as a single point in the upper layers of the skin and slowly enlarge, both along the surface and downward. These extensions cannot always be seen directly. The tumour often extends far beyond what is visible on the surface of the skin. Basal cell carcinoma metastasis (spread) is extremely rare, and usually only occurs in the setting of long-standing, large  tumours. Squamous cell carcinoma is slightly more dangerous and patients must be observed for any spread of the tumour. Such spread is still infrequent. Patients with basal cell, squamous cell carcinoma and  certain rare neoplasms should ideally be treated by this technique if they fall within one of the following criteria:

• Recurrent skin cancer
• Skin cancers occurring in sites where recurrence rates with traditional approaches are high (eg. around the eyes, nose and lips)
• Incomplete removal of tumour
• Large tumours (greater than 2cm in diameter)
• Tumors with indistinct skin margins

What are the advantages of Mohs Surgery?

• The highest cure rate
• Minimal removal of normal, tumour-free tissue
• Performed under local anaesthesia as an outpatient, although general anaesthesia facilities are available if required
• Reconstructive surgery takes place under optimum conditions
• Because Mohs surgeons are also dermatologists who have training in reconstructive surgery, they have extensive knowledge of the skin and its healing properties, which helps produce the best cosmetic result
• Procedure is usually completed within half a day

What are the risks involved in Mohs Surgery?

• The exact size of the final defect, following clearance, cannot be predicted prior to surgery. The tumour may be much larger than estimated from the surface appearance
• A scar will remain at the site of removal. Every effort is made to obtain optimum cosmetic results, but the primary goal is always to remove the entire tumour
• As a patient, you should understand there is no absolute guarantee that any procedure will be totally free of complications or adverse reactions
• There may be loss of motor (muscle) or sensory (feeling) nerve function in the rare instance where a tumour involves nerve fibres. The nerves must be removed along with the tumour, and if a sensory nerve is injured or removed, numbness results. Sensation will usually, but not always, return
• Rarely, a few patients experience intermittent shooting pain at the surgical area, however this is a very unusual complication
• Because tumours often occur in the head and neck, many are near or on vital structures such as the eyes, nose or lips. In such cases, portions of these structures may have to be removed with resulting cosmetic or functional deformities
• The surgical area may remain tender for several weeks or months after surgery if large amounts of tissue were removed
• Skin grafts and flaps used to cover surgical areas may occasionally not survive