Each year, over 1.2 million cases of skin cancer are diagnosed. Many of these are adequately treated by simple surgical excision or electrodessication and curettage. Surgery is effective for most types of skin cancer, but is most used to treat basal and squamous cell carcinomas, tumors that have recurred after previous surgery or tumors in cosmetically important areas. Mohs surgery has been proven effective in treating skin cancer by combining the surgical removal of cancer with the immediate microscopic examination of the tumor and underlying diseased tissue. This allows the Mohs surgeon to see beyond the visible disease and precisely identify and remove the complete tumor and a conservative amount of surrounding tissue.
The method requires both sequential excision of tissue and preparation of special frozen sections for microscopic examination under local anesthesia in the following steps:
- The area is anesthetized using a long-acting local anesthetic.
- A thin layer of tissue-surrounding and including the tumor is excised.
- A dressing is applied to the area and the patient will be able to rest while the next step of the process takes place. This will take 45-60 minutes.
- A map is drawn that corresponds exactly to the patient’s tumor.
- The excised tissue is sectioned and each section given a number which is indicated on the map, already drawn.
- Each section is frozen and stained with chemicals which highlight cancer cells.
- Each section is examined under the microscope by your doctor. If the tumor is still present on any section, it is marked on its corresponding section of the map.
- Since the map corresponds exactly to the patient’s tumor, the physician can go back and locate the exact area where the skin cancer was found on the section microscopically. If necessary, another thin layer is removed from the appropriate location.
The entire procedure is repeated until all areas are free of cancer. Once the removed tissue shows no signs of cancer, the above process stops, preserving healthy, normal tissue and closure of the defect takes place. Mohs surgery ensures that all and only the diseased tissue is removed, therefore minimizing the scar from the cancer removal.