What you need to know about Mohs surgery

What is Mohs Surgery?:  Mohs surgery is a specialized surgical treatment for skin cancer.   When detected and treated early, almost all skin cancers are completely curable.  You were referred for Mohs because it offers the highest cure rate for your type of skin cancer, including skin cancers in cosmetically and important areas on the face.  Mohs involves surgically removing skin cancer layer by layer and examining the tissue under a microscope to be sure the tumor is removed entirely and only healthy, cancer-free tissue remains.  


How to prepare for Mohs Surgery:  No real preparation, other than a good night’s sleep, is required. Eat a light breakfast on the day of surgery. If you are currently taking medication, continue as usual unless directed otherwise by your physician. Depending on your medical history, you may be asked to stop aspirin or any medications containing aspirin for two weeks before surgery. This is because aspirin tends to prolong bleeding during the operation. Also, avoid medications containing ibuprofen, commonly found in Advil, Nuprin and Motrin, for at least three days before surgery. If you need a pain reliever, you may take acetaminophen, which is found in Tylenol.  If you are prescribed blood thinners by your doctor (coumadin, xarelto, eliquis), please do not stop these without talking to your doctor.


It is best to wear a shirt that buttons down the front. No makeup or jewelry should be worn if surgery is to be performed on your face. Bring a good book or magazine with you, as you will spend a significant amount of time waiting while the microscopic slides are prepared and interpreted.  You may also want to bring snacks and a lunch as you may spend most of the day with us on your Mohs day.  


* Please do not use  5-Fluorouracil (Efudex, Carac) for 2 weeks before or 2 weeks after your procedure.


The Mohs Surgery process- what to expect on the day of Mohs Surgery:  Shortly after your arrival, you will be taken to one of the treatment rooms, where the tumor area will be numbed with a needle under local anesthesia.  


The Mohs surgeon will remove a layer of skin surrounding the cancer. You will then be bandaged and be able to return to the waiting room.  A map of the area is carefully drawn so that the surgeon can precisely locate any skin cancer that may remain.  By this time, the removed tissue will be in our Mohs laboratory. There, it is cut, dyed and made into microscopic slides for the Mohs surgeon to review. It usually takes 20-30 minutes for the layer of tissue to be removed. However, it takes about 1 hour for the tissue to be prepared into microscopic slides for examination. During this time you may chat with the person accompanying you, read a book or step out for fresh air.


If examination of the microscopic slides reveals that your tissue still contains tumor cells, the procedure will be repeated. Further tissue is removed only from the areas where tumor cells were found, using the map created.  The average number of Mohs surgery stages required to clear a tumor is one to three. However, you may require more before your skin cancer is completely removed.  Because skin cancers can grow deeply and develop roots extending beyond the area that you see, the final size of the surgical wound will be determined by the extent of your tumor.  When surgery is completed, a decision will be made as to the way to manage your wound.


How Mohs wounds are managed:  Once it has been determined that your skin cancer has been completely removed, your surgeon will discuss with you options to manage your wound. In some instances, the wound may be allowed to heal by itself – this is called “healing by granulation” or by “second intention.”   In other cases, the wound needs to be repaired with stitches, a skin graft, or a skin flap from the surrounding areas. The decision will depend on the size and location of your wounds. If a repair is needed, this usually can be done the same day.  In a minority of cases, depending on the size and location of the defect, the Mohs surgeon will work with trusted surgical colleagues to coordinate a repair of the surgical defect.

If stitches are placed, you will likely be asked to return to the office in 1-2 weeks for suture removal.  If your wound is left to heal by itself, you will need daily bandage changes until the wound heals.  The time to heal varies by location- for example, on the face it may be days to weeks, but on the legs it can take many weeks or even a few months depending on the size.  You will be given written instructions on how to change your bandages. 


What to expect after Mohs Surgery?

Pain: Most patients do not have severe pain, but may experience slight discomfort.  If this occurs, we suggest taking tylenol.  

Bleeding: Occasionally, bleeding follows surgery. If this happens, do not become alarmed. Lie down and place steady, firm pressure over the wound as close as possible to the bleeding area. Apply firm pressure continuously for 20 minutes (timed). Do not lift the bandage to check on the bleeding. If bleeding persists after 20 minutes of steady pressure, apply pressure for an additional 20 minutes. If bleeding still continues, call our office at (215) 315-3197, or go to the nearest hospital emergency room.

Swelling: Swelling is very common following surgery, particularly when it is performed near the eye. All wounds swell a little. Usually this is not a problem, and the swelling diminishes as the wound heals. Ice packs around a cloth may help to reduce the swelling.  Sleeping with an extra pillow can also help with facial swelling.

Drainage: All wounds drain to some extent during the first week or two. This is why dressing changes are necessary.

Infection. Infection of the wound is rare. However, if you see thick, foul-smelling fluid coming from the wound, please call our office immediately.  Other signs of infection to look for include increased redness, warmth of the site, fever, and pain that is getting worse.  An antibiotic may be necessary.

Redness: All wounds will develop some redness, which fades gradually. If the area becomes extremely red, it could be a sign of infection.  If the area becomes red and itchy you may be allergic to either the ointment or tape. Call our office if this condition develops.

Scarring. All surgeries leave a scar. However, your scar will improve and become less noticeable as time passes.  Fortunately, scars on the face heal better than any other place on the body.  


What to expect after your wound appears healed:  Most patients have no to minimal issues after Mohs surgery.  In some instances, you may experience some tightness as the wound heals. This is normal and usually lessens with time. Patients also may experience itching as their wounds are healing. Frequently, the tumor and the surgery may involve nerves in your skin, and it may take up to a year, or even two years, before normal feeling returns to an area. Unfortunately, rarely the area treated can remain numb permanently. 


In some people, the scar tissue around the wound contains more blood vessels than the surrounding skin.  This results in a red scar. This usually improves with time and the redness gradually fades.  Sometimes portions of the scar become thick and this can be managed with local injections of a medication to reduce thickening.  


Very rarely, a scar is unacceptable If this is the case, surgical scar revision may be considered. However, we usually advise patients to wait 12 months before having a scar revision performed. This is because the scar continues to improve in appearance and becomes less conspicuous up to one year after surgery.


Follow-up visits: After Mohs you will likely be asked to follow-up in 1 to 3 weeks for wound checks.  After that wound check visits may be scheduled as needed.  Once your surgery is over and your wound has healed, we recommend you follow-up with your general dermatologist. These visits can help with early detection and treatment of new skin cancers that may develop as well as the rare recurrence of the skin cancer that was treated. If you notice any suspicious areas on your skin between visits, it is best to check with your dermatologist to see if a biopsy is needed.