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Mohs Surgery FAQs
Here are answers to some of the most common questions patients ask about Mohs surgery.
This unique form of surgery for skin tumor removal was developed more than 50 years ago by Frederick Mohs, MD, a professor at the University of Wisconsin. Since that time, the technique has been refined and advanced. In fact, today it is offered in most major medical centers throughout the country. Its wide acceptance stems from the fact that, for certain kinds of skin cancer, it offers a cure rate of upwards of 99 percent.
Mohs surgery is performed by a specialty trained team that includes a physician, several surgical assistants, a technician who prepares the tissue for microscopic examination, and the office staff. You will meet the entire team at the time of your consultation and/or surgery.
Patients with biopsy-proven skin cancer
Patients whose cancer is located on their head or neck
Patients with recurrent cancer at any site
Patients who have had the surgery recommended to them by a dermatologist
Mohs surgery is performed on an outpatient basis. First, local anesthesia is used to numb the tumor site. Then, as much of the visible tumor as possible is taken off by scraping with a special instrument. A thin layer of skin at the tumor site is then removed and examined under a microscope. If evidence of tumor cells is found at the edges of the sample, the doctor will remove and examine another skin sample. These steps will be repeated until no tumor can be detected under microscope. Depending on the extent of the tumor, this process may be repeated several times.
Although the actual surgery involved in each sampling takes only 20 minutes, the entire process may take upwards of one hour per sample. As we cannot determine ahead of time how many stages you will require, be prepared to spend the entire day with us. It very rarely takes more than one day to remove a tumor.
The major advantage of Mohs surgery is that by tracking the tumor-removal process microscopically, we better ensure that the entire tumor is removed.
Another important advantage of this technique is that by using a microscope to guide us, we remove only the tissue which the tumor has already invaded, sacrificing little of the surrounding healthy skin. This is important if the cancer is close to an important feature, especially on the face. Of course, any procedure will leave a scar, but by preserving the maximum amount of healthy skin, we strive to allow the best possible cosmetic result.
We cannot know ahead of time the extent of your tumor. It is difficult, therefore, to discuss the repair of the surgical site until the procedure is completed. However, there are several ways of repairing the skin. Small or superficial wounds may be left to heal by themselves. Larger wounds may need to be stitched closed. The largest wounds may require a flap or a graft. Both techniques involve moving healthy skin from elsewhere on your body to repair the surgical wound. When the tumor has been completely removed, and we know the size and shape of the resulting wound, we will be better able to discuss the best options for repair. Most patients have their wound repaired on the same day the Mohs procedure is performed.
Complications of Mohs Surgery
Some bleeding during surgery is expected. It is uncommon, however, for bleeding to occur after surgery.
Infection occurs rarely. If it does occur, it is controlled by oral antibiotics.
Most scars are numb because sensory nerves have been cut. Sometimes adjacent skin is also numb. Rarely is a tumor located around nerves that control movement. In such cases, muscle movement may be impaired as a result of nerve damage caused by the removal of the tumor.
Allergic reaction can occur due to the local anesthesia or the bandage.
There is usually not much pain or discomfort after surgery. In fact, most people return to their normal daily activities the next day, although the site is usually bandaged for two to six weeks.
A scar will always result from Mohs surgery. Scars usually mature over several months and become cosmetically acceptable. Some scars will be pink and bumpy for three to nine months. Scars that do not mature well can often be cosmetically altered. If surgery is needed to improve the appearance of a scar, the procedure is usually performed 12 months after the original surgery.
Tumors recur in some patients even after Mohs surgery has been carefully performed. A recurrence will usually look like a small bump or red scaly area on or close to the surgical site. Recurrences are not usually apparent for one to three years. Recurrences are almost always treated again with Mohs surgery because of the technique’s high cure rate.