Understanding
Mohs Micrographic Surgery
At Sora Dermatology,
Kimberly Shao, MD is our
Mohs surgeon.
She is a double board-certified and ACGME fellowship-trained in Mohs micrographic surgery, dermatologic oncology, and reconstructive surgery.
She has performed over 4000 surgeries and was trained in specialized reconstructive techniques that aim for scarless outcomes. She will be diligent in her review of repair options with you so that you can make an informed decision together.
What is Mohs micrographic surgery?
Mohs micrographic surgery is the most effective treatment for skin cancer available today. Initially developed by Dr. Frederic E. Mohs in the 1930s, this technique allows for precise removal of skin cancers layer by layer, while sparing surrounding healthy tissue.
The first goal of Mohs surgery is to cure your skin cancer. Since your doctor serves as both your surgeon and your pathologist, she will be able to confirm same day that your skin cancer has been cleared.
The second goal of Mohs surgery is to reduce potential scarring or disfigurement. The Mohs surgery technique overall allows for smaller scars as the surgeon is able to leave as much normal tissue unharmed as possible.
How effective is Mohs micrographic surgery?
Mohs micrographic surgery offers the highest chance for complete removal of the tumor while sparing normal tissue surrounding it.
Clinical studies have demonstrated Mohs surgery has the highest cure rate of all treatments for skin cancer—up to 99 percent—making it the treatment of choice for cancers of the face and other cosmetically sensitive areas.
How does Mohs differ from a standard wide local excision?
Mohs
Exceptional Cure Rates: Mohs surgery has the highest cure rate for skin cancer. The exceptional cure rate of Mohs surgery stems from its evaluation of 100% of the margin before surgical repair.
Highly Precise: Mohs surgery involves the removal of skin cancer layer by layer. Each layer is meticulously examined for remaining skin cancer. Underneath the microscope your surgeon can determine exactly where to take an additional layer, if one is needed.
Tissue Sparing: Mohs surgery often uses 1-3 mm margins per layer and aims to preserve as much healthy tissue as possible, resulting in smaller scars and improved cosmetic outcomes.
Standard Excision
Good Cure Rates: Standard excision has cure rates of 92-95% for non-melanoma skin cancers. With a standard excision technique, less than 1% of the true margin is evaluated.
Less Precise: Because the tissue is not examined the same day, there is a chance that patients may have to return for additional surgery because the tumor is found to be incompletely removed after being sutured closed.
Wide Margins: Wide local excision uses standard margins ranging from 4-6 mm for non-melanoma skin cancers. This can ultimately end up in larger scars compared to Mohs surgery.
Who is Mohs micrographic surgery recommended for?
Mohs micrographic surgery is primarily used to treat skin cancers on high-risk areas where tissue preservation, aesthetic appearance, and functional outcome are of vital importance.
The most common types of skin cancers Mohs micrographic surgery treats are basal cell carcinoma and squamous cell carcinoma.
The most common locations that Mohs surgery is used for include: nose, ears, lips, eyelids, other parts of the face, scalp, neck, hands, feet, and genital region.
Other factors that contribute to meeting criteria for Mohs surgery include: large size, recurrent tumors, tumors in scar tissue, aggressive tumors, patients who are immunosuppressed.
How should you prepare for your Mohs surgery?
We always recommend a Mohs consultation, especially if you have never had Mohs surgery before. Dr. Shao can walk your through the details of the Mohs day, and answer questions you may have about the procedure and your aftercare so that you feel prepared on the day of your surgery.
Refrain from smoking or using nicotine products 2 weeks before your surgery and during the healing process.
Avoid alcohol 24 hours before and after your surgery.
Showering the night before or the morning of is advised. You may be unable to get your bandage wet for 24-72 hours.
On morning of your procedure, you should take all of your normal medications as prescribed, unless your surgeon tells you otherwise. You should also eat breakfast. You do not need to fast for this surgery.
Mohs surgery can last almost the entire day. Pack your favorite snacks and even a lunch with you. There is a TV in every room and access to Wifi, but some patients like to bring other activities with them like a book. Remember to bring any medications that you may need with you.
Wear loose, comfortable clothing
Avoid wearing make-up if the surgery is on your face
How is Mohs micrographic surgery performed?
Step 1: The surgeon will come in and review the plan for the day as well as mark the site. The area to be treated will be numbed.
Step 2: Then the first layer will be taken. The first layer includes the visible skin cancer or scar plus a narrow 1-2 mm margin around the tumor. The first layer will go to as deep as at least the fat layer.
Step 3: Next, the tissue will be brought to our lab where a histotechnician will process it. This can take a few hours. The surgeon will then look at the layer underneath the microscope, examining both the peripheral and deep margins. If there is still skin cancer present, another layer will be taken. This process is repeated until no tumor cells are detected (Steps 4 & 5). Importantly, each time a new layer goes to the lab it may take another couple hours to process. This is why we can’t predict how long your Mohs day might be.
Step 6: Once your skin cancer is cured, the surgeon will then discuss repair options with you. Sometimes patients decide to let wounds heal naturally without any stitches. Most often a wound is sutured close in a line. There are some scenarios where a linear closure is not possible, and a flap (taking nearby tissue and bringing it over to cover the wound) or a graft (taking tissue from a completely different area and suturing it onto the wound) may be recommended.
Step 7: If stitches are elected for, the wound will in most cases be repaired on the same day as your Mohs procedure.
Step 8: After your repair, the medical assistant will bandage the area and go over wound care instructions. An appointment for suture removal may be made before you go home.
When will I be referred to another specialist?
In rare cases, you may be referred to another specialist following Mohs surgery for further treatment or reconstruction.
Dr. Shao has considerable experience in Mohs surgery and repairs in even challenging areas of the body; however, some patients prefer their closure under sedation/general anesthesia. We can happily help coordinate this for you.
If a skin cancer is extensive or has a number of high-risk factors, additional work-up such as genomic testing, imaging, or lymph node testing or additional treatment with a radiation or medical oncologist may be strongly recommended.
What are the disadvantages of Mohs surgery?
Mohs micrographic surgery is just that – surgery. That means it comes with numbing injections, risks of infection, tenderness, swelling, bruising, and potential scarring.
Please see our “Alternatives for Mohs Micrographic Surgery” page (coming soon!) for other options and how they compare to Mohs surgery.
Additionally, while Mohs surgery offers unparalleled precision and effectiveness, it is labor-intensive and time-consuming. On average, a patient may be in our office for a Mohs procedure anywhere from 3 to 6 hours. Complicated cases can take even longer. We understand that this is a long and stressful day and will do everything we can to make you as comfortable as possible.
Please see our “Tips for your Mohs Day” (coming soon!) for more detailed recommendations about ways you can prepare. We appreciate the patience of you and the family/friends that you bring with you.