Skin cancer is the most commonly diagnosed cancer in the United States with an estimated 1,000,000 new cases per year. The three most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma, and malignant melanoma. There are several kinds of treatment for skin cancer; the majority of these treatments are surgical. These include simple excision (cutting) and suturing (stitching), curettage and electrodessication (scraping and burning with an electric needle), and Mohs surgery (microscopically controlled excision). Occasionally, X-ray therapy is used. The method chosen depends on the size and location of the cancer, the type of cancer, and previous therapies (if the cancer is a recurrence). Melanomas are almost always treated by wide-excision. On the other hand, basal cell carcinomas and squamous cell carcinomas can be treated by any of the above methods.

Not all treatments for skin cancer are equal. Although any of the above methods can be used to treat basal and squamous cell carcinomas, Mohs micrographic surgery is by far the most superior. Mohs surgery offers the highest cure rate (up to 99%), the lowest chance of regrowth, the lowest potential for scarring and disfigurement, and the most exact and precise means of removal (only skin cancer is removed, normal tissue is spared). In 1941, Dr. Frederic Mohs first described the technique of removing skin cancers under microscopic control. Since that time, various modifications have been made, but the essential premise of the technique is unchanged; that is, to verify under microscopic control the removal of the skin cancer at the time of surgery. (This is in contrast to standard excision which relies on an outside pathology lab to verify the removal of the skin cancer. Often, the skin cancer has not been completely removed, and the patient must be subjected to a second excision). Once the skin cancer is removed by the Mohs technique, the surgeon can then safely reconstruct the defect to minimize any cosmetic disfigurement. Thus, the excision and reconstruction are all done on the same day.

Mohs surgery relies on the physician serving as surgeon, pathologist, and reconstructive surgeon. The procedure starts with the administration of a local anesthetic to the area to be excised. Once the area is numb, the visible skin cancer is removed with a small margin of normal-appearing skin (this is called the first layer or stage). The tissue is then marked and mapped so that the Mohs surgeon knows the orientation of the specimen relative to the site it came from. Following processing of the tissue, it is examined under the microscope. If any of the sections contain cancer cells, the Mohs surgeon marks it on his 'map' and returns to the patient to remove an additional thin slice of tissue from the specific area where cancer cells were detected. This process is repeated until the specimens show no cancer cells. Often, it takes 2-3 stages to completely remove the skin cancer. Once the skin cancer is removed, the 'defect' is then 'repaired' or 'reconstructed' using 'plastic reconstructive' techniques (i.e. flaps and grafts); this usually involves suturing (stitching). Usually the sutures are removed one week later.

Mohs surgery is an advanced surgical technique, which is performed by specially trained dermatologists who have completed fellowship training. (Such physicians are members of the American College of Mohs Micrographic Surgery and Cutaneous Oncology.) It is performed on an outpatient basis, under local anesthesia. It is the treatment of choice when the cancer is large, the edges of the cancer are poorly-defined, the cancer is in an area of the body where it is important to preserve normal healthy tissue (i.e. eyelids, nose, ears, lips), or the cancer has failed prior treatment.