Everything You Need to Know Before Mohs Surgery for Skin Cancer by Dermatologists
By David Hashemi, MD, MBA and David G. Li, MD, MBA
David Hashemi is a board-certified dermatologist and Mohs Surgery and Cosmetic Dermatology Fellow. Previously he was a resident at the Harvard Medical School Combined Dermatology Program.
David Li is a board-certified dermatologist in private practice in downtown Boston and the Founder of BDA. Previously he was a resident at the Harvard Medical School Combined Dermatology Program.
Table of Contents
Overview: Precision Surgery for Skin Cancer Removal
What Types of Skin Cancer is Mohs Surgery Used For?
What are the Benefits of Mohs Surgery?
How to Prepare for Mohs Surgery
What to Expect During the Mohs Procedure
What’s the Process for Reconstruction After Mohs?
Recovering After Mohs Surgery and Wound Care Essentials
Potential Risks and Complications
If you've been diagnosed with skin cancer, your dermatologist may recommend Mohs surgery. As the most effective technique to treat high-risk skin cancers, Mohs offers the highest cure rates while removing as little healthy skin as possible.
In this complete guide, our team of board-certified dermatologists and Mohs fellow will explain what Mohs surgery involves, what to expect during the procedure, recovery, and aftercare. We'll also cover the best ways to prepare for surgery, so you feel ready.
Overview: Precision Surgery for Skin Cancer Removal
Mohs micrographic surgery, also known simply as Mohs surgery, is a highly specialized technique for skin cancer removal. It aims to remove all cancerous cells for the highest cure rate while preserving precious healthy skin surrounding the tumor.
This method was developed in 1938 by Dr. Frederic Mohs. The key advantage is precise layer-by-layer examination of tissue under the microscope until margins are completely clear. This meticulous approach allows for a rigorous degree of cancer elimination without taking more normal skin than absolutely necessary - critical around delicate areas like the eyes, nose, ears, hands, and genital areas (among others). In addition, Mohs surgery is considered the standard of care treatment for high-risk skin cancers beyond their location on the body, including recurrent skin cancers and those with a higher risk behavior under the microscope.
Mohs procedures are highly effective at curing skin cancer while minimizing recurrence, with recurrence rates as low as 1% depending on the type of skin cancer. It’s considered the treatment of choice for high-risk cancers or those in cosmetically sensitive locations.
What Types of Skin Cancer is Mohs Surgery Used For?
Mohs surgery can remove several forms of skin cancer:
Basal cell carcinoma (BCC) - Most common skin malignancy. While many BCCs on the body can be treated with standard excision, Mohs is preferred for BCC occurring in sensitive cosmetic areas or with large, recurring, or high-risk BCC.
Squamous cell carcinoma (SCC) - Second most common skin cancer. Mohs results in better cure rates for high-risk tumors especially on nose, ears, lips, hands and feet.
Melanoma - Although standard excision is often used for melanoma, Mohs may allow for more narrow but complete margins, particularly in cosmetically sensitive areas such as the head and neck areas. Some of the literature even suggest that there may be lower recurrence rates with Mohs for melanoma.
(See Brodland DG. Mohs Micrographic Surgery for Melanoma: Evidence, Controversy, and a Critical Review of Excisional Margin Guidelines. Dermatol Clin. 2023 Jan;41(1):79-88)
Rarer skin cancers - Merkel cell cancer, dermatofibrosarcoma protuberans and other cancers.
Mohs is also considered when patients have a genetic disease which causes frequent or aggressive skin cancer recurrence.
What are the Benefits of Mohs Surgery?
Advantages Mohs offers over standard excision techniques:
✅ Highest cure rate - microscopic precision to trace and ensure full removal results in up to 99% cure.
✅ Complete margin evaluation - by removing the skin cancer in a horizontal fashion and examining special frozen sections, surgeons can evaluate 100% of the surgical margin (compared to 1% in standard non-Mohs excisions)
✅ Tissue sparing - Only cancerous areas are continually targeted, leaving the maximal safe amount of normal skin.
✅ Ideal for delicate structures - Preserves form and function around eyes, nose, lips, ears, hands, feet, and genitals.
✅ Cost-effectiveness - High initial success reduces or avoids future expenses due to further treatments, disfigurement, or metastases
✅ Fast procedures & healing - The concentrated precision enables most cases to be performed, microscopically cleared, and repaired in the same day with great cosmetic results.
✅ Low recurrence rates - Meticulous removal and margin analysis means cancer recurrence likelihood drops to 1 to 3%.
Not all skin cancers require Mohs surgery. For easily closed wounds expected to heal with minimal scarring, traditional surgical excision can suffice for low-risk tumors using a standard margin. Your dermatologist or surgeon will advise if standard techniques or Mohs is most appropriate based on location, size, and type of skin cancer diagnosed.
How to Prepare for Mohs Surgery
Make arrangements for transportation to and from the surgery.
Take a thorough shower washing hair included the night before and morning of. This minimizes the risk of infection.
Have a meal before you come in (breakfast if your surgery is in the morning, lunch if it’s in the afternoon) so you aren’t hungry while waiting. If you are seeing a Plastic Surgeon after your Mohs surgery, or if sedation is being used for your procedure, discuss with your physician whether you should avoid eating beforehand.
Bring snacks and something to read or do while waiting between stages.
Avoid taking any non-steroidal anti-inflammatory agents such as Motrin, Ibuprofen, Advil, Celebrex, Nuprin, Feldene, Clinoril, Alleve, Naprosyn, or Anaprox for pain relief for 2 days before surgery. For minor aches, pains, and headaches, take regular or extra-strength Tylenol (acetaminophen) as directed on the label.
Take your regularly prescribed morning medications the morning of surgery, unless otherwise advised.
Avoid Vitamin E, supplemental garlic tablets, or Gingko biloba for 2 weeks before surgery.
If possible, avoid alcoholic beverages for 1 week (or at least 3 days) leading up to surgery, as alcohol can increase the risk of bleeding.
If possible, stop smoking (or reduce smoking significantly) for at least 2 weeks before and after surgery, as smoking can impair wound healing.
Wear loose, comfortable clothing. Do not wear your finest clothing. Ideally, surgeons recommend a button-down shirt that will not disrupt post-operative dressing changes later that night.
Set up a recovery space at home with supplies like gauze, paper tape, and cold compresses.
Plan for 2-3 weeks off work allowing proper time to rest and heal. Time off depends on the surgery extent and complexity.
Arrive on the day of surgery relaxed, well rested, and wearing loose, comfortable washable clothes.
If you have any questions leading up to the procedure, ask your Mohs surgeon. Understand in advance what skin repair options (grafts, flaps, other reconstructive methods) might be necessary based on scope and location. Preparation leads to smooth, successful surgical experiences.
What to Expect During the Mohs Procedure
The basic steps of Mohs surgery:
Numbing medication (local anesthetic is injected) is used so no pain is felt during the procedure.
The visible portion of the cancer gets removed surgically.
You may be asked to wait in a relaxing setting such as the waiting room pending results.
The tissue layer removed gets divided into sections and immediately examined under the microscope.
If cancer cells are still detected under the microscope in any section, the surgeon draws a careful map and takes another thinly sliced layer of skin only from the involved area of remaining cancer.
Steps 2-5 repeat until no more cancer is visible under microscopic analysis. This confirms clear margins.
Once cancer free margins are achieved, the surgical defect gets closed by stitches or possibly a skin flap or graft depending on the wound and location.
So Mohs distinguishes itself by its precision approach to carefully map, remove, and verify all skin cancer prior to repairing the site. This tissue-sparing technique helps optimize appearance after healing by leaving as much normal skin as possible.
What’s the Process for Reconstruction After Mohs?
Once clear margins are fully achieved, repair of the surgical defect begins. Goals guiding optimal reconstruction:
Choose technique preserving maximal function (e.g. closing eyelids properly)
Carefully align skin creases/tension lines
Repair layers accurately for durability and contour
Promote as aesthetically pleasing results as possible
Consider options should the repair breakdown or scar unfavorably
Reconstruction method depends variables like:
Where on the body surgery was performed
Layer depth involved
Wound size and shape
Laxity of surrounding skin
Options available to surgeon performing repair
Some closure approaches include:
Direct suture closure - Bringing skin edges together
Local skin flaps - Moving adjacent skin sections into the defect
Full thickness grafts - Placing skin segments from elsewhere on the body
Healing by secondary intention - Allowing wounds to close up naturally
Reconstructive surgery - Sometimes a plastic surgery referral becomes necessary for complex repairs
Your Mohs surgeon will discuss repair recommendations to restore the area optimally. This last surgical step allows patients to have complete treatment and continued healing.
Recovering After Mohs Surgery and Wound Care Essentials
Recovery from Mohs varies based on factors like:
Size of defect after tumor removal
Reconstruction technique performed
Location on the body operated upon
But in general you can expect:
Mild pain and discomfort for a week, typically well-controlled with over-the-counter pain medication.
Bruising, swelling and drainage around incisions and dressings.
Careful dressing changes and keeping wounds moist and protected.
Avoiding smoking, alcohol, exercise, and sun exposure.
Following all post-op directions diligently including restrictions and medications.
Once sutures are removed, keep the area protected from the sun to avoid prolonged darkening of the area. At the time of suture removal, your Mohs surgeon may also recommend silicone scar gels, scar sheets, and/or firm massage when indicated. Please check with your Mohs surgeon regarding the timing of using these.
Refer closely to written discharge instructions from your surgeon for wound care and restrictions after Mohs surgery to optimize healing. Proper care reduces chances of bleeding, poor scar quality, and infection. Don't hesitate to contact the surgeon with any questions or worrisome symptoms.
Potential Risks and Complications
Despite high effectiveness, rare risks with Mohs surgery can occur:
Recurrence - Even with meticulous technique, skin cancer cells may very rarely be missed resulting in persistence or relapse. Rigorous ongoing follow up helps detect this early for prompt retreatment.
Infection - Though infection is uncommon, any surgery carries some risk of infection requiring antibiotics.
Poor wound healing - Related to bleeding, insufficient oxygen delivery, nutrition deficits and other factors interfering with optimal repair. Smoking impairs this greatly.
Scar or graft complications - Scars may widen, restrict movement, or become raised or discolored. Skin grafts also don't take fully in some cases. Steroids, laser therapy, or surgical scar revision may then be necessary.
Make sure you realistically understand possible complications and commit to strict aftercare to achieve the best possible results from Mohs surgery. Notify your doctor about any concerning symptoms for prompt management. Some revisions or secondary procedures may be necessary in more complex reconstructions - and this possibility should be planned for in advance when agreeing to treatment.
What Does Follow Up After Mohs Surgery Involve?
A post-op visit may typically occur 1 to 2 weeks later to inspect wound healing, change dressings, remove any stitches, and discuss pathology results.
If healing normally, subsequent checks happen at around 6 weeks, 6 months, and a year out. Regular skin exams with your primary dermatologist continue lifelong, though the timing should be individualized for each patient.
Photographs will be taken at follow ups to compare surgical sites over time to catch any concerning changes emerging early.
Any symptoms like bleeding, expanding redness, pus, fever, or intense pain should prompt urgent contact with your surgeon.
Plan on skin checks every 6 months (more frequently for high-risk patients), with self-exams monthly in between. Prevention and detection become lifelong.
Photographs, questions, and skin assessments will be key parts of long-term care. Speak up about any worries or changes you want evaluated. Partnership with your dermatology team ensures the best outcomes long term.
Conclusion
Undergoing Mohs surgery to eliminate skin cancer can raise anxiety given its precise nature and the need to excise layers until margins are clear. But when facing high-risk tumors or difficult to treat locations, this method provides the greatest chance for permanent removal while preserving healthy tissue for optimal function and cosmetic outcomes. It offers an unparalleled cure rate using state-of-the-art techniques perfected over decades.
If Mohs gets recommended for your skin cancer, learn everything you can beforehand about the multi-step procedure, recovery protocols and what to expect in the long term. Ask any questions not covered to your full satisfaction. Preparation and understanding set the stage for effective treatment tailored exactly to your needs. With an experienced, compassionate Mohs surgeon supporting you, this process can remove anxiety over facing skin cancer and let you move positively towards healing.
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What is Mohs surgery?
The skin cancer foundation defines Mohs surgery as a precise method to remove skin cancer. It is also called Mohs micrographic surgery. The surgeon removes thin layers of skin and examines them under a microscope until no cancer remains.
Why is Mohs surgery preferred for certain types of skin cancer surgery?
Mohs surgery is favored because it allows for evaluation of the full margin, ensuring highest-possible cure rate and preservation of as much healthy skin as possible. The method allows for the affected area to be examined under a microscope while the patient is still in the operating room.
How is Mohs surgery performed?
Mohs surgery is performed by a specially trained surgeon who uses Mohs surgery to treat skin cancer. The surgeon may use local anesthesia to numb the area, then a scalpel to remove a layer of tissue. The removed tissue is then examined under a microscope and, if cancer is found, another layer is removed.
What is the goal of Mohs surgery?
The primary goal of Mohs surgery is to remove the entire skin cancer but as little healthy skin as possible until no cancer cells remain. This approach is especially beneficial for common types of skin cancer.
What can be expected during the Mohs surgery procedure?
During the procedure, the patient is typically awake and functioning. The surgeon removes one layer, processes, and evaluates the tissue, and repeats, if necessary, until the cancer has been entirely removed from the patient's body. The area is then repaired or allowed to heal to optimize cosmetic appearance.
When is Mohs surgery typically recommended?
Mohs surgery is commonly recommended for skin cancer located in areas where it is essential to conserve as much healthy skin as possible, such as the face, ears, hands, feet, genitals, and scalp, or in higher-risk tumors.
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We are a group of dermatology residents and attending physicians based in Boston, MA. Our team of Ivy League-trained dermatologists is demystifying the cosmeceutical industry by offering unbiased, scientifically supported reviews of skincare products. We are extremely passionate about skincare and making it accessible to all through education. We value integrity, practicality, and inclusivity. No sponsorships were received for the products prior to testing; we feel strongly about providing un-biased reviews. After blogs are published, following the links in this blog post may result in commission.
