Mohs Micrographic Surgery: An Overview

New treatments for skin cancer are appearing and evolving rapidly in recent years. However, one surgical technique has more than stood the test of time. Developed by Dr. Frederick Mohs in the 1930s, Mohs micrographic surgery has, with a few refinements, come to be embraced over the past decade by an increasing number of surgeons for an ever-widening variety of skin cancers.

Today, Mohs surgery has come to be accepted as the single most effective technique for removing Basal Cell Carcinomas and Squamous Cell Carcinomas (BCCs and SCCs), the two most common skin cancers. It accomplishes the nifty trick of sparing the greatest amount of healthy tissue while also most completely expunging cancer cells; cure rates for BCC and SCC are an unparalleled 98 percent or higher with Mohs, significantly better than the rates for standard excision or any other accepted method.

The reason for the technique's success is its simple elegance. Mohs differs from other techniques in that microscopic examination of all excised tissues occurs during rather than after the surgery, thereby eliminating the need to "estimate" how far out or deep the roots of the skin cancer go. This allows the Mohs surgeon to remove all of the cancer cells while sparing as much normal tissue as possible. The procedure entails removing one thin layer of tissue at a time; as each layer is removed, its margins are studied under a microscope for the presence of cancer cells. If the margins are cancer-free, the surgery is ended. If not, more tissue is removed from the margin where the cancer cells were found, and the procedure is repeated until all the margins of the final tissue sample examined are clear of cancer. In this way, Mohs surgery eliminates the guesswork in skin cancer removal, producing the best therapeutic and cosmetic results.

In the past, Mohs was rarely chosen for Melanoma surgery for fear that some microscopic melanoma cells might be missed and end up spreading around the body (metastasizing). However, efforts to improve the Mohs surgeon's ability to identify melanoma cells have led to special stains that highlight these cells, making them much easier to see under the microscope. Thus, more Mohs surgeons are now using this procedure with certain melanomas. With the rates for melanoma and other skin cancers continuing to skyrocket, Mohs will play an ever more important role in the coming decades.