What you should know about Mohs Surgery:
For people with the more common non-melanoma skin cancers, basal cell and squamous cell carcinoma (BCC and SCC), a technique known as the Mohs surgery is often used. Mohs surgery is preferred when treating many BCCs and SCCs. It’s the single most precise and effective method for eliminating these cancers in most cases.
Your chance of developing a non-melanoma skin cancer in your lifetime is about one in five. Exposure to ultraviolet (UV) light, either from the sun or from indoor tanning, is the greatest risk factor for most people. The head and neck are the main areas that are affected because the exposure is the greatest. Unfortunately, skin cancers on the face are the most prominent and most cosmetically challenging. These are especially capable of becoming disfiguring and dangerous if not caught at an early stage.
Mohs Surgery has the lowest recurrence rates, highest cure rates and best cosmetic results of any skin cancer treatment. The procedure is cost-effective because the cancer removal, microscopic evaluation and, in most cases, wound reconstruction are all done in one visit. The reported cure rate is over 98 percent.
It’s important to understand what Mohs surgery is, how it works and how it treats cancer while allowing you to look your best after surgery.
Mohs Micrographic Surgery–How It Works
Dr. Frederic Mohs invented the Mohs micrographic surgery at the University of Wisconsin. It didn’t develop into a mainstream treatment until practitioners such as NYU dermatologist and Skin Cancer Foundation founder Perry Robins, MD, refined the technique and spread the word about it in the 1970s and 1980s. In the past 15 years, this surgery has become the most popular choice for skin cancers in the head and neck region.
Mohs micrographic surgery is a highly specialized, state-of-the-art technique used for the treatment of complex skin cancers. Mohs surgeons are dermatologists who have performed additional fellowship training to become experts in Mohs micrographic surgery. Fellowship-trained Mohs surgeons are highly skilled in all aspects of this technique, including surgical removal of the cancer, pathologic examination of the tissue, and advanced reconstruction techniques of the skin. Let’s take a look at the following in detail:
Indications to use Mohs Surgery
- the cancer is in an area where preservation of healthy tissue is critical to maximize function and cosmetic result (eyelids, nose, ears, lips, hands)
- the cancer is in an area of higher tumor recurrence (ears, lips, nose, eyelids, temples)
- the cancer was incompletely treated, or was previously treated and is recurrent
- the cancer is large
- the edges of the cancer cannot be clearly defined
- scar tissue exists around the cancer
- the cancer grows in an area of prior radiation therapy
- the patient is immune suppressed (organ transplant, HIV infection, chronic lymphocytic leukemia)
- the patient is prone to getting multiple skin cancers (including genetic syndromes such as basal cell nevus syndrome and xeroderma pigmentosa
A repeated series of surgical excisions followed by microscopic examination of the tissue is required to assess if any tumor cells remain during the Mohs surgical process. Usually, on clinical examination some tumors that appear small may have extensive invasion underneath normal appearing skin, resulting in a larger surgical defect than would be expected. Hence, it is impossible to predict a final size until all surgery is complete. Approximately half of all treated tumors require 2 or more stages for complete excision.
Steps in Detail
Step 1: Anesthesia
The surgeon may first draw some marks around the lesion with ink to guide the treatment, and then injects a local anesthetic to completely numb the tissue. General anesthesia is not usually required for Mohs micrographic surgery.
Step 2: Removal of visible tumor
Later the tumor is gently scraped with a curette, a semi-sharp, scoop-shaped instrument once the skin has been completely numbed. The Mohs surgeon removes the first thinnest possible layer of visible cancerous tissue. An electric needle may be used to stop the bleeding. A nurse or assistant bandages the wound and shows you to a waiting area or you remain in your examination room. The surgeon then color-codes the tissue with ink to map exactly where it was removed from the body.
Step 3: Mapping the tumor
Once a “layer” of tissue has been removed, a “map” or drawing of the tissue and its orientation to local landmarks (e.g. nose, cheek, etc) is made to serve as a guide to the precise location of the tumor. The surgeon makes sure to label and color-code the tissue to correlate with its position on the map. The surgeon then processes the tissue sections and examines it to thoroughly evaluate for evidence of remaining cancer cells. The entire process, staining and examining of the tissue takes approximately 60 minutes.
Step 4: Additional stages-Ensuring all cancer cells are removed
The surgeon will remove another thin layer of tissue from the precise area where the cancer cells were detected if any tissue demonstrates cancer cells at the margin. And the same procedure is repeated with the tissue removed. It is again mapped, color-coded, processed and examined for additional cancer cells. If microscopic analysis still shows evidence of disease, the process continues layer-by layer until the cancer is completely removed to make sure all the cancerous cells are removed. Mohs surgery allows the complete removal of the cancer without harming the normal tissue.
Step 5: Reconstruction
In order to preserve normal function and maximize aesthetic outcome, reconstruction is individualized. After the cancer is removed, the best method of repairing the wound following surgery is determined, because the final defect cannot be predicted prior to surgery. Stitches may be used to close the wound side-to-side, or a skin graft or a flap may be designed. Sometimes, a wound may be allowed to heal naturally.