Mohs Micrographic Surgery
Mohs micrographic surgery is a specific surgical technique that seeks to deliver the following 3 clinical outcomes:
- The highest chance for complete cure.
- The lowest recurrence rate of any skin cancer treatment method.
- The most optimal cosmetic result.
Developed by Dr. Frederick Mohs, in the 1930s, Mohs micrographic surgery is the single most effective technique for removing basal cell carcinomas and squamous cell carcinomas (cure rates of 98% or higher), the two most common types of skin cancers.
The Mohs micrographic surgery technique is designed to be “tissue sparing.” Through specialized training, your St. Luke’s Mohs surgeon removes cancer cells while leaving behind the greatest amount of healthy, non-cancerous skin possible. When you consider that up to 80% of all basal cell carcinomas and squamous cell carcinomas occur on the head and neck, you realize just how important it is to protect this skin for cosmetic and functional reasons.
Not all skin cancers are appropriate for Mohs micrographic surgery. Small, superficial basal cell carcinomas or squamous cell carcinomas on the abdomen, chest, back, arms and legs are usually considered “low risk.” These cancers are usually treated adequately by standard treatments such as surgical excision, cryosurgery (“freezing”), curettage and electrodessication (“scrape and burn”), photodynamic therapy, and/or topical medications.
Areas that are considered “high risk” and most appropriate for Mohs micrographic surgery include those cancers that affect the nose, the eyelids, lips, ears, hands, feet, and genitals; areas on the face, scalp, neck and shins are considered “intermediate risk.” Other skin cancers for which the Mohs micrographic surgery technique may be appropriate include:
- Cancers that have recurred or that were never completely removed by other treatments
- Large cancers (even in normally “low risk” areas)
- Cancers with poorly demarcated borders
- Certain distinct microscopic patterns that suggest higher aggression
- Cancers that occur in patients whose immune systems are weakened by disease (leukemia, HIV/AIDS) or medications (such as transplant recipients)
- Cancers that occur in patients with predisposing genetic syndromes
A key difference between Mohs micrographic surgery and traditional excisional surgery is that the Mohs surgeon personally examines the skin cancer slides under the microscope. Another key difference is that the Mohs technique requires the tissue sparing surgery to be completed in stages. The Mohs micrographic surgeon usually starts by confirming that the area being operated on, indeed, has a skin cancer still present; this is usually accomplished by comparing clinical photographs to previous biopsy reports. Next, the affected area is usually photographed, and then the surgeon marks around the skin cancer with ink to help guide treatment. An anesthetic agent is placed to completely numb the skin. Then, using a scalpel, the Mohs surgeon removes a thin layer of skin and then color-codes the removed tissue to create an “ink map” that correlates with exactly from where on the body the tissue was removed. An assistant bandages your wound, and you are invited back to the waiting area while the removed tissue gets processed. A technician, next, processes the removed skin in an on-site Mohs micrographic laboratory; this includes freezing the skin and slicing the tissue into thinner-than-paper sections that are then placed on glass slides and stained. Your Mohs micrographic surgeon personally examines these slides under a microscope. If no cancer cells remain in a given area, then that area is deemed clear of cancer. If any cancer cells do remain, then they are pinpointed on a map. You are then brought back to the Mohs procedure room, and the surgeon removes another layer of skin – repeating this process until you are free and clear of cancer in all of the microscopically-examined areas.
This entire process does not require you to wait days for lab results to come back as seen with traditional excisional surgery. Instead, your Mohs micrographic surgeon performs the entire procedure immediately, while you wait on site. The entire process may take several hours from start to finish, and it is worth it for the high cure rate and cosmetic outcome.