Mohs micrographic surgery is a highly specialized procedure for the total removal of skin cancers under microscopic control. The procedure is named in honor of the physician who first developed this technique approximately 50 years ago, Dr. Frederick Mohs, professor of surgery at the University of Wisconsin.
Removal of certain types of cancer under continuous microscopic control results in the smallest possible wound and highest rate of cure: 95% to 99% in some cases.
Mohs micrographic surgery is universally recognized as a precise method for treating skin cancers. Mohs is especially effective in cancers of the face and other sensitive areas, such as the hands, fingers, neck and scalp.
What Is Mohs Micrographic Surgery?
Mohs micrographic surgery is also ideal for the removal of recurrent skin cancers–tumors that reappear after treatment and can plague a patient repeatedly. While skin cancers are easily visible to the patient, individual cancer cells are microscopic and any cells left behind can cause the tumor to reappear. The tumor may spread beyond its obvious external margins with “nests” of cells growing in unpredictable areas.
With the Mohs technique, all tumor nests can be identified and removed with a high degree of accuracy, so extremely high cure rates, as high as 95% to 99%, are possible even when the cancer is recurrent. A board-certified dermatologist is best trained to determine when this technique should be used rather than another effective procedure for treating skin cancer.
“Mohs surgery is a safe and proven surgical procedure that helps thousands of people lessen the fear of skin cancer. We encourage early diagnosis and treatment for optimum results.”
Jessica Scruggs Dorsey, M.D., Board-Certified Dermatologist, Fellow of the American College of Mohs Surgery, Dermatology Associates of Central Texas
How Is Mohs Surgery Performed?
Not all tumors grow as perfect spheres. What is visible on the surface of the skin may be only the tip of the tumor that exists underneath the skin. There are several different modes of tumor growth that are best treated using the Mohs technique. The keys to the Mohs technique include:
- Serial excision of a tumor using strict anatomical orientation.
- Examination of tissue using a microscope.
- Mapping the exact location of the residual tumor for the total removal of skin cancer.
In Mohs surgery, multiple thin, horizontal layers of the cancer are analyzed. Tumors may send tentacles of malignancy below the surface, beyond the visible boundaries. The main differences between micrographic surgery and other methods of removing skin lesions is the microscopic control.
The tumor is removed surgically with a margin of presumed healthy tissue around and below the lesion. The removed tumor is divided into segments, each of which is carefully oriented on a “map.” Each layer is carefully identified and “mapped” by the surgeon, so its exact location can be pinpointed on the wound. Every layer of tissue removed is inspected under the microscope for evidence of cancer cells.
As long as cancer cells are seen anywhere within the specimen, the surgeon continues to remove the tissue until no cancer cells are present. Because each layer is examined microscopically, dermatologists can be reasonably certain that the cancer has been eradicated and that no tumor nests are left behind. Only the cancerous tissue is removed, saving as much normal skin as possible.
Mohs micrographic surgery is commonly performed on an outpatient basis with a local anesthetic administered to the area around the tumor. Surgery usually begins early in the morning and is finished the same day unless the tumor is extensive. Because of the layer-by-layer removal, laboratory preparation and examination under the microscope are delicate and require great precision.
If more than one session is needed to remove all signs of a tumor, a dressing is applied. Once the area is declared cancer-free, your surgeon will discuss the options of wound healing or reconstructive surgery.
Periodic visits to your dermatologist are recommended to check on your progress and spot any possible cancer recurrence as soon as possible. Two of every five patients with one skin cancer will develop another within five years, so follow-up is extremely important for early detection of any new lesions.
Why Mohs Surgery?
Cure rates for skin cancer after treatment with Mohs micrographic surgery are as high as 95% to 99%. The technique produces the smallest possible wound in the removal of any given tumor. The smaller the wound, the greater the chances are for a good cosmetic result after the wound has completely healed. This is particularly important on the face, where a good appearance after surgery is of concern to the patient.
An overwhelming majority of tumors can be totally removed in one treatment session, due to the preciseness of the surgery and microscopic inspection. While the Mohs surgery is a technically demanding procedure, it is also highly cost-effective, because fewer return visits to the dermatologist´s office are needed for treatment of a recurring lesion.
Are You a Good Candidate for Mohs?
You may not be a good candidate for Mohs if you are unable to tolerate local anesthesia, have extreme anxiety, have a surgical phobia, or are in very poor health.
Your decision on the best treatment choice may depend on different factors such as the location and type of skin cancer, your past treatments, your overall health, and level of comfort with the procedure. Your physician can help you sort through the different treatments and assist in your shared decision-making process.
Do You Have Implants or Health Issues?
Your Mohs surgeon needs to know of you have any underlying medical conditions that may affect your surgery or wound healing. Discuss any artificial parts or implants such as knees or hips, a pacemaker or defibrillator, or if you need to take antibiotics before dental procedures because of a heart condition or murmur.
Your Mohs surgeon needs to know if you have had a history of staph or other skin infections in the recent past. You may be asked to wash with a special antibiotic soap a few days before surgery to help reduce the number of bacteria on your skin.
Patients need to also advise their surgeon of any drug allergies to anesthetics like Lidocaine, Xylocaine or Novocain. Additionally, the surgeon may need to know of any bleeding or bruising tendencies, hepatitis, HIV/AIDS or pregnancy.