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 microscopic control results in the smallest possible wound and highest cure.
Although the concept of Mohs micrographic surgery was developed over 50 years ago, relatively few dermatologists were trained in its use until recently. Only in the last few years has the technique become widely available throughout the country.
Mohs micrographic surgery is now universally recognized as a precise method for treating skin cancers. It is especially effective in cancers of the face and other sensitive areas, because it can eliminate virtually all the cancer cells while causing minimal damage to the surrounding normal skin.
Mohs micrographic surgery is also ideal for the removal of recurrent skin cancers which 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 that extremely high cure rates – as high as 95 percent – are possible even when the cancer is recurrent.
A dermatologist is best trained to determine when this technique should be used rather than the other effective procedures also available for treating skin cancer.
Mohs micrographic surgery may be called Mohs surgery, chemosurgery, microscopically controlled surgery or histographic surgery – but they are all the same. In the years since Dr. Mohs pioneered the procedure, many technical improvements and refinements have contributed to make micrographic surgery a safe and highly effective means of treating skin malignancies.
The main difference between micrographic surgery and other methods of removing skin lesions is microscopic control. In Mohs surgery multiple thin, horizontal layers of the cancer are removed. The surgical removal proceeds along a grid pattern, with each layer carefully identified and "mapped" by the surgeon so that its exact location can be pinpointed on the cancer site. 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 diseased tissue until none are present.
Because each layer is examined microscopically, dermatologists can be reasonably certain that all the cancer has been eradicated and that no tumor nests are left behind. In addition, 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.
Layer-by-layer removal, laboratory preparation and examination under the microscope are painstaking and require great precision. They are also time consuming. 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. One of 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.
Cure rates for skin cancer after treatment with Mohs micrographic surgery are as high as 95 percent. The technique produces the smallest possible wound in the removal of any given tumor. The smaller the wound, the greater the chances 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 a highly cost-effective, because fewer return visits to the dermatologist's office are needed for treatment of a recurring lesion.