Mohs Micrographic Surgery and Reconstructive Surgery
Mohs surgery is the most effective treatment for most types of skin cancer including basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). With the Mohs technique, we can precisely identify and remove an entire tumor while leaving the surrounding healthy tissue intact and unharmed.
The Department of Dermatology at Mount Sinai is a world leader in this procedure. We have cured more than 50,000 skin cancers with this procedure and we continue to perform more than 2,000 cases a year. We also have an extensive Mohs training program for dermatologists.
The Mohs procedure involves surgically removing skin cancer layer-by-layer. We examine each layer under a microscope until we reach healthy, cancer-free tissue around the tumor (called a clear margin). Mohs surgeons are trained as a cancer surgeon, pathologist, and reconstructive surgeon. Mohs surgery has the highest success rate of all treatments for skin cancer – up to 99 percent.
Advantages of Mohs surgery include:
- Ensuring complete cancer removal during surgery, dramatically decreasing the chance of cancer growing back
- Minimizing the amount of healthy tissue lost
- Maximizing the functional and cosmetic outcome
- Providing a highly effective approach to cancer treatment
Other skin cancer treatment methods estimate the amount of tissue that needs to be treated, which can result in the unnecessary removal of healthy skin tissue and tumor re-growth if any cancer is missed.
Why Choose Mohs Surgery
Because of Mohs surgery's high success rate, most patients require only a single surgery. This procedure usually includes the repair of the wound as well. Other methods might require additional surgeries and pathology readings in order to repair the wound and to treat the cancer if it is not completely removed. Each of these additional surgeries and pathology readings require separate fees and affects the surrounding tissue.
Mohs surgery minimizes the emotional toll as well. You do not have to wait for the results of one procedure and schedule another. In addition, since Mohs minimizes the risk of recurrence, it leads to peace of mind. It also reduces the costs of larger, more serious surgeries for recurrent skin cancers.
There are a few things you can do to prepare for Mohs surgery. Stop taking ibuprofen (such as Advil or Motrin) or other oral non-steroidal anti-inflammatory drugs (NSAIDs) seven days before surgery. You should check with your doctor about other blood-thinning medications such as aspirin, heparin, dipyridamole (Persantine), pentoxifylline (Trental), clopidogrel (Plavix), prasugrel (Effient), ticagrelor (Brilinta), warfarin (Coumadin), dabigatran (Pradaxa), rivaroxaban (Xarelto) and apixaban (Eliquis). If you take any herbal medications (such as St John’s wort, ginkgo biloba, vitamin E, garlic, ginseng, fish oil) that predispose you to bleeding and bruising, you should avoid those. Do not drink alcohol for 48 hours prior to surgery.
On the morning of surgery, you should eat a normal breakfast and take your regular medications. Wear comfortable clothing. You may want to bring something to read or pass the time because there will be waiting time between stages of Mohs surgery.
Typically, surgery starts early in the morning and is completed the same day, depending on the extent of the tumor and the amount of reconstruction necessary.
Removing the Tumor
We start by numbing your skin with a local anesthetic. This means that you are awake and comfortable during the entire procedure. Using a local anesthesia rather than general anesthesia shortens the recovery time and decreases possible side effects.
Your Mohs surgeon starts by removing the visible tumor and a thin layer of surrounding tissue. Then a technician prepares this tissue on slides for your surgeon to examine under a microscope. If the surgeon sees evidence of cancer around the outer edges of the removed tissue, he or she takes another layer of tissue from the area where the cancer was detected. This approach ensures that we remove only cancerous tissue and a small margin of clean tissue, minimizing the loss of healthy tissue. Your surgeon repeats these steps until all samples are free of cancer. It usually takes one to three stages to completely remove the tumor with clean margins.
Once we are confident that all the cancer is removed, we can reconstruct the remaining skin. The Mohs surgeon can usually do this immediately after the tumor removal stage. Sometimes we delay reconstruction to a later day.
Our goal with reconstruction is to leave the least visible scar possible. When we plan reconstruction, we take into consideration the tumor’s size, depth, and location as well as your preferences.
While your surgeon might be able to give you an idea of whether your reconstruction should take place immediately after surgery or be delayed until later, it is impossible to know the extent of the cancer in advance.
Typically, we use one of these reconstruction options:
- We allow small, simple wounds to heal by themselves (called secondary-intention healing)
- We close slightly larger wounds with side-to-side stitches
- For larger or more complicated wounds, we may use a skin graft from another are of the body or close the wound with a flap using skin adjacent to the wound
- We may refer you to another reconstructive surgical specialist such as a Mount Sinai specialized oculoplastic surgeon or a facial plastic surgeon
After the Procedure
You should have little or no pain after the procedure. Acetaminophen (Tylenol®) or, in rare instances, a stronger painkiller such as ketorolac (Toradol®), should take care of any discomfort. Major complications are rare with Mohs surgery. You may experience some minor swelling and bruising, but that will fade in a few days. Some people have an allergic reaction to the adhesive tape, but that too goes away quickly. If you have any minor bleeding, just apply firm pressure to the area. Infections are rare, but easily treated with antibiotics.
Healing time varies, depending on your age, medical history, and type of operation. Sutured wounds usually heal in two to three weeks. Skin grafts may take a month or two. For wounds that heal by granulation (secondary-intention), the healing time is usually one to three months. We will give you specific aftercare instructions before you leave our office.
You will return to your Mohs surgeon at Mount Sinai who will remove the sutures and change the dressing. We normally see you after one week for procedures on the face or neck and two weeks for procedures performed on the body or limbs. We also schedule follow-up appointments after a month or two to discuss treatments that can improve scars.
Because you have had skin cancer, you should see your dermatologist regularly for cancer checks and if you notice any concerning changes on your skin.
Mohs surgery is the most effective treatment for most types of skin cancer. We have provided answers to several common questions about Mohs skin cancer surgery below.
Why is it called Mohs surgery? Is Mohs an acronym?
The term "Mohs" refers to Dr. Frederic Mohs, Professor of Surgery at the University of Wisconsin, who developed this surgical technique in the 1930s. The technique has undergone many refinements since.
What is Mohs surgery?
Dr. Mohs recognized that a skin cancer often resembles the "tip of the iceberg" with more tumor cells growing downward and outward into the skin like the roots of a tree. These "roots" are not visible with the naked eye, but can be seen under a microscope.
Mohs surgery is a highly specialized and precise treatment for skin cancer in which the cancer is removed in stages, one tissue layer at a time. It is an outpatient procedure, performed under local anesthesia, and is distinguished by a specific technique of tissue examination that is unique to Mohs surgery. Although other surgical specialists may check excision margins, this form of pathologic examination of the tissue is not the same as Mohs surgery.
Once a tissue layer is removed, its edges are marked with colored dyes, and a map of the specimen is created. The tissue is then processed onto microscope slides by a Mohs histotechnician. These slides are carefully examined under the microscope by the Mohs surgeon so that any microscopic roots of the cancer can be precisely identified and mapped. If cancer cells are seen, an additional tissue layer is removed only in areas where the cancer is still present, leaving normal skin intact. This saves as much normal, healthy skin as possible.
Once the cancer has been removed, the Mohs surgeon will explain options for repair of the wound, including natural healing (granulation), stitching the wound together using a side-to-side closure, or using a skin flap or graft.
I don't see anything after my biopsy. Do I really need to be treated?
Yes. Following a biopsy, your skin cancer may no longer be visible. However, the surface lesion that was removed can represent the "tip of the iceberg." There may be more tumor cells in the skin. These can continue to grow downward and outward, like roots of a tree. These "roots" are not visible with the naked eye. If they are not removed, the tumor will likely reappear and require more extensive surgery. On rare occasions, these cancerous cells can spread (metastasize) to lymph nodes and other organs in the body.
Why does my skin cancer need to have Mohs surgery?
Mohs surgery has the highest cure rate. It is appropriate for most skin cancers and especially suitable for skin cancer that:
- Is in an area where it is important to preserve healthy tissue for maximum functional and cosmetic result
- Was treated previously and has come back
- Is located near scar tissue
- Is large
- Does not have clearly defined edges
- Is growing rapidly or uncontrollably
- Is of an aggressive subtype (i.e., sclerosing or infiltrating basal cell carcinoma)
- Develops in organ transplant or lymphoma patients
Please note: the above list is not exhaustive of all of the instances where Mohs surgery is the most appropriate option for your skin cancer.
How long does Mohs surgery take?
The length of surgery is different for every patient and is difficult to estimate prior to the actual procedure. It depends on the extent of the tumor, which we do not know until we start removing it. Although Mohs surgery can take longer than other approaches, advances in technology, such as automated staining of tissue samples, have made it quicker. Typically, the entire procedure lasts several hours. Your Mohs surgeon may be able to give you a clearer sense of the timeframe you can expect
Will Mohs surgery leave a scar?
Yes. Mohs surgery will leave a scar, like any other treatment for skin cancer.
Mohs surgery preserves as much healthy skin as possible and maximizes options for repairing the surgical defect, once the tumor is completely removed. Once the Mohs surgeon has completely removed your skin cancer through Mohs surgery, reconstruction that optimizes the final functional and cosmetic result becomes the highest priority. Generally, a post-surgical scar improves with time and can take up to 1 year or more to fully mature. As your surgical site heals, new blood vessels can appear and support the healing changes occurring underneath the skin. This can result in a reddish appearance of the scar. This change is temporary and will improve with time.
In addition, the normal healing process involves a period of skin contraction, which often peaks 4 to 6 weeks after the surgery. This may appear as a bumpiness or hardening of the scar. On the face, this change is nearly always temporary and the scar will soften and improve with time. If you have a history of abnormal scarring, such as hypertrophic scars or keloids, or if there are problems with the healing of your scar, injections or other treatments may be used to optimize the cosmetic result. Your Mohs surgeon is available for you throughout the healing process to discuss any concerns that may arise.
Is Mohs surgery the most cost-effective treatment option?
Because of Mohs surgery's high success rate, most patients require only a single surgery. This surgery usually includes the repair of the wound as well. Other methods might require additional surgeries and pathology readings in order to repair the wound and to treat the cancer if it is not completely removed. Each of these additional surgeries and pathology readings require separate fees, while a single Mohs surgery procedure includes all of these into one fee.