Mohs micrographic surgery for melanoma.

The results of multiple investigators have confirmed the value of Mohs surgery in the treatment of melanoma. In addition, these studies have contributed to our understanding of the biologic behavior of melanoma. The success of Mohs surgery confirms that melanoma grows in a contiguous fashion before it spreads systemically. It is known that once tumor breaks away from the main mass, trying to improve survival by increasing the extent of conventional surgery is often fruitless. Therefore, the goal of surgery is to remove all of the tumor, including the silent contiguous foci. If melanoma did not grow in a contiguous fashion before metastasis, the results of Mohs surgery would be inferior to wide excision, and higher local recurrences would be expected. Instead, the excellent results support the concept of contiguous tumor growth. Satellites and in-transit metastases that appear later may be removed with the fixed-tissue technique. We have also learned that melanoma sends out silent contiguous extensions, necessitating excision of some normal-appearing skin. The width of those extensions is unrelated to the depth of the melanoma. The value of Mohs surgery is the ability to identify these extensions microscopically and to excise tumor-bearing tissue while sparing normal skin. In fact, Mohs surgery often spares a diameter of 1.8 cm or more when compared with standard surgery, a distinct advantage to patients whose melanomas are on the head, neck, hands, feet, or genitalia or in patients whose melanoma has indistinct clinical margins and would require an even wider margin of normal skin when using standard surgical techniques. We now have long-term results from large numbers of patients--confirmed by multiple investigators and data--to support the concept of Mohs surgery for melanoma. This information emphasizes the important role that Mohs micrographic surgery plays in the treatment of melanoma.