WHAT IS MOHS SURGERY?
Mohs surgery (MS) is a specialized and very effective method of removing skin cancers. Developed by Frederic Mohs, M.D. at the University of Wisconsin, MS is now practiced throughout the world. MS permits the surgeon to ensure that all the “roots” of a skin cancer have been removed. Mohs surgery has the highest reported cure rates of any form of skin cancer.
Most skin cancers do not require MS. It is reserved for skin cancers that have re-grown after previous treatment, are at greater risk for growing back, or are located in areas where preservation of normal skin is important. MS is practiced by surgeons who have received specialized education, either during or after their residency training.
WHEN IS MOHS SURGERY RECOMMENDED?
Some skin cancers are much larger under the skin than they appear on the surface. These may grow into and below the skin and along blood vessels, nerves, or cartilage. Cancers that have come back again after treatment may also grow deeply and under scar tissue. MS is specifically designed to track and remove the “roots” of these cancers.
HOW IS MOHS SURGERY PERFORMED?
Mohs surgery requires three steps:
1) The skin is first made completely numb using a local anesthetic. The visible cancer is removed along with a thin layer of additional tissue. This takes only a few minutes and patients may then return to the waiting room. A diagram (called a Mohs map) of the surgery site is drawn.
2) The specimen is carefully oriented and processed. A technician freezes the tissue and removes very thin slices from the entire undersurface. These slices are placed on microscope slides and prepared for the surgeon to exam under the microscope. This step is the most time consuming, often requiring 20 to 60 minutes.
The surgeon then examines the slides to determine whether any cancer remains. The size and location of any cancer roots are pinpointed on the Mohs map. The surgeon then uses the Mohs map as a guide to remove additional tissue only where cancer roots are present. This is why the Mohs surgery technique leaves the smallest possible surgical wound, because there is no guess work involved in deciding where to remove additional tissue. Only tissue around the roots and extensions of cancer is removed.
HOW LONG DOES MOHS SURGERY TAKE?
Most cases are completed in less than four hours, while larger or more complex cases may take longer. No one can predict in advance how extensive a given cancer will be. You should reserve the entire day for your surgery.
WILL THE SURGERY LEAVE A SCAR?
Yes, any form of surgery leaves a scar. The scar will usually be smaller than those from other forms of skin cancer surgery.
WHAT HAPPENS AFTER THE MOHS SURGERY IS COMPLETED?
After the cancer is removed, the surgeon will discuss with you whether 1) to allow the wound to heal naturally, without additional surgery, 2) to repair the wound that day, or 3) to have a different surgeon repair the wound.
WILL I HAVE PAIN, BRUISING, OR SWELLING AFTER SURGERY?
Most patients do not have significant pain, and over-the-counter pain medications often control it. Stronger prescription pain medications are prescribed, when needed. Discuss any concerns you have about pain control with your surgeon. You will almost certainly have some bruising and swelling, especially if surgery is being done close to the eyes.
WILL MY INSURANCE COVER THE COST?
Most insurance policies cover the cost of both MS and the surgical reconstruction of the wound. Please check with your insurance carrier for exact information relating to your surgery.
HOW DO I PREPARE MYSELF FOR SURGERY?
Get a good night’s rest and eat normally the day of surgery. Bring reading material to occupy your time while waiting for your slides to be processed and examined. Also, you should consider arrange for someone to drive you home after surgery is completed.
If you are taking prescription medications, continue to take them unless otherwise directed by your surgeon. You must inform your surgeon, in advance, if you are taking any medications or supplements that can thin the blood. These include Coumadin, Plavix, baby aspirin, ibuprofen, Advil, Motrin, Naprosyn, etc. Many supplements, including ginseng, garlic, gecko, ginko belloba, vitamin E, and niacin will thin your blood. You may be asked to stop taking some or all of your supplements before your surgery.
Howard K. Steinman, M.D.
Associate Professor of Dermatology
Director, Dermatologic and Skin Cancer Surgery Department of Dermatology Texas A&M University Health Sciences Center College of Medicine