MOHS surgery, a technique used primarily for non-melanoma skin cancers, both removes skin cancers and preserves the healthy tissue around it. The procedure starts with the removal of the obvious tumor. Then the surgeon removes another thin slice of tissue from the same area. It is sectioned to create a map and examined under a microscope while the patient waits. If that tissue shows evidence of further disease, the procedure is repeated until the removed tissue is clean of any cancer cells.