Mohs Micrographic Surgery: The Most Advanced, Effective Skin Cancer Treatment Available
Mohs surgery is a highly specialized surgical technique for the removal of skin cancer. Mohs surgery is unique because it allows the surgeon to remove all of the skin cancer while leaving the smallest defect possible. Mohs surgery has proven to be the gold standard for the treatment of many types of skin cancer and offers the highest cure rate.
During Mohs, the tumor is removed and the surgeon then analyzes 100 percent of the removed tissue under the microscope to be sure all of the margins are free of cancer. This outpatient procedure is performed under local anesthesia and is usually followed by reconstruction of the area.
Mohs is performed by an American College of Mohs Surgery fellowship-trained dermatologic surgeon who has completed additional surgical training beyond a traditional dermatology residency. The Mohs surgeon is specially trained in surgery, pathology, and reconstruction.
What can I expect if I am having Mohs surgery?
The goal of Mohs surgery is to remove all of the skin cancer while preserving the greatest amount of healthy tissue. However, skin cancers can develop roots deep into the skin, extending beyond the area that you actually see. Before surgery begins, the Mohs surgeon will review the medical history with the patient. Mohs surgery is performed in a series of well-planned steps as follows:
1) Identifying the site:
The area involved with skin cancer is marked and cleaned with surgical prep.
2) Numbing the site:
Next, the cancer and the surrounding normal skin will be injected with a local anesthetic. After the anesthetic has taken effect, the patient will not feel any sharp pain; feeling some pressure in the area is normal.
3) Defining the cancer's border:
The first step in surgery is to remove portions of the tumor with curettage (scraping). The surgeon will curette the lesion until s/he no longer sees or feels any visible tumor. The surgeon may choose not to curette all tumors, depending on the type and size of the tumor.
4) Outlining the cancer's border:
The surgeon will then cut out the cancer along with a small amount of normal-appearing skin that surrounds the cancer.
5) Mapping the tumor:
The surgeon will then make carefully planned marks at the tumor edges to map the tumor so that it may continue to be oriented to the skin while being processed into slides. In the picture to the left the surgeon has made a series of notches in the tumor and normal skin/ this will easily allow the tumor to be oriented to the skin once it is removed.
6) Removing the tumor:
After the surgeon has cut completely around the tumor, s/he will then cut underneath the tumor. Surgical removal of the cancer is performed in a specific fashion so that the entire undersurface and all of the skin edges can be examined systematically under the microscope by the Mohs surgeon.
7) Waiting for clear margins:
Once the tumor is completely removed the wound will be cleaned and bandaged. The patient will be free to do whatever s/he wants while the tumor is processed in the laboratory.
8) Tumor mapping:
During this time, a map of the tumor will be drawn to help identify the sections of the tumor that will be created and placed onto slides.
9) Inking the tissue:
In the lab, the Mohs technician will then cut the tumor into either halves or quarters. The technician applies special colored dyes to the tumor and will then identify the locations of the dyes on the map to help the surgeon orient the tissue so that any tumor found microscopically can be located in the exact right spot on the patient.
10) Slide preparation:
Next, the tissue will be frozen and sliced into very thin sections that will be applied to slides.The slices of tissue are placed onto slides and the slides are then dipped into different wells that contain various dyes and washes. This process will help stain the tissue to be visible under the microscope.
11) Slide examination:
The Mohs surgeon then examines the slides under the microscope to look for cancer cells. He will look for any parts of the slide that contain cancer. If no cancer cells are found, that means the tumor has been completely removed, the patient is cancer-free and the defect can be repaired (see step #15 below). However, if cancer cells are found, more tissue will need to be taken at the exact spot where cancer cells still remain.
12) Identifying areas that still have cancer:
The surgeon then marks the map any area where cancer is still present. This will identify which areas must be removed. In the picture to the left, there was cancer identified in the top right, bottom right, and bottom left. This patient then underwent a second stage of surgery to remove these cancerous areas.
13) Removing areas still positive for cancer:
More local anesthetic is injected and then subsequent tissue is removed in a similar fashion until no more cancer cells are seen under the microscope. No additional tissue was removed from the top left area of the skin, and this area will be preserved for the rest of the surgery. The average number of surgical sessions required is one to three. Fortunately, this can usually be done over the course of a single day.
A new map is made and once again the skin is stained with dyes and prepared for viewing on slides. The new slides are viewed by the Mohs surgeon to look for the presence of any remaining cancer. In this case, the patient was clear of tumor after two stages of surgery.
14) Patient is cancer-free:
The tumor has been cleared and the patient is now ready for repair of the defect.
15) Repairing the defect:
For the last stage of the surgery, the Mohs surgeon will use various techniques to reconstruct the area with the goal of giving the best cosmetic result.
16) The surgery is now complete and the defect has been repaired.
Not all wounds will be closed this way; the Mohs surgeon will decide the best way to close the wound depending on the size and location of the defect. The patient is asked to return at a later scheduled date to have the sutures removed. The scar has already begun to heal in this patient and will continue to heal for the next several months.
The History of Mohs Surgery
The Mohs Surgery technique was initially developed by Dr. Frederic Mohs in Wisconsin. Over the past 70 years, the technique has been perfected. Mohs founded the American College of Chemosurgery in 1967. In 1988, the name was changed to The American College of Mohs Micrographic Surgery and Cutaneous Oncology. On the college's 40th anniversary in 2007, the name was changed to its current name, the American College of Mohs Surgery.
Mohs Surgery performed live on ABC's Good Morning America!
Back to Top