What is Mohs Skin Cancer Surgery?
Microscopically controlled surgery was developed by Dr. Frederick Mohs in the 1940s as a more precise way to remove skin cancers. Originally, chemicals were applied to the skin and the entire surgical procedure took several days. The technique has been refined over the years to the point where the skin cancer is now removed and examined under the microscope for any remaining tumor almost immediately. The basic principle behind the Mohs technique is to remove the entire skin cancer without taking any more normal skin than is absolutely necessary.
Often what can be seen on the skin surface represents only a part of the actual skin cancer, "the tip of the iceberg" so to speak. With our eyes alone, we cannot see the "roots" of the skin cancer that are under the skin surface. Instead of guessing how far these "roots" extend under and around the skin cancer, the microscope is used to trace and map the exact extent of the tumor. The surgeon may then remove only the cancerous tissue. This prevents either removing too little and leaving the tumor behind to come back, or recur (usually larger) in the future, or from removing too much and creating a larger than necessary wound. In essence the best of both worlds is achieved. The entire skin cancer is removed and as much as possible of the normal skin is preserved. The Mohs microscopically controlled technique offers a cure rate of 98-99%, the highest of any technique available.
Since Mohs surgery requires highly-trained personnel and can be time consuming, it is reserved only for certain cases. The four most common indications for using the Mohs technique are:
The tumor is located on a structure that is so important that one wishes to remove only the diseased tissue and preserve as much of the normal skin as possible (face, hand, etc...)
The cancer has been previously treated and has come back (recurred)
The margin or extent of the tumor cannot be discerned
The tumor occurs in an area of the body where it is not effectively curable with other methods