Mohs Micrographic Surgery
Skin Cancer is by far the most common malignant tumor in humans. The most common types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma. Both basal cell carcinoma and squamous cell carcinoma begin as a single point in the upper layers of the skin and slowly enlarge, spreading both along the surface and downward. These extensions cannot always be directly seen. The tumor often extends far beyond what is visible on the surface of the skin. If not completely removed, both types of skin cancer may invade and destroy structures in their path. Although these skin cancers are locally destructive, they do not tend to metastasize (spread) to distant parts of the body. Metastasis of basal cell carcinoma is extremely rare and usually occurs only in the setting of long-standing, large tumors where the patient’s immune system is compromised. Squamous cell carcinoma is more dangerous, and patients must be observed for any spread of the tumor. Such spread is still infrequent. Melanoma is a very different and more dangerous kind of skin cancer and is not treated with Mohs Micrographic Surgery.
Excessive exposure to sunlight is the single most important factor associated with the development of skin cancers. In addition, the tendency to develop these cancers appears to be hereditary in certain ethnic groups, especially those with fair complexions and poor tanning abilities. Fair-skinned people develop skin cancers more frequently than dark-skinned people, and the more sun exposure they receive, the more likely they are to develop a skin cancer. Other factors, including exposure to radiation, trauma and exposure to certain chemicals, may also be involved in the development of skin cancers.
Skin cancers may be more aggressive in certain instances: patients whose immune system is compromised, patients with a medical history of leukemia or lymphoma, cancers in certain locations such as the ear, lips, nose, or around the eyes.
Skin Cancer Therapies
There are various methods for the treatment of skin cancers. The nonsurgical treatments are cryotherapy (deep freezing), Aldara cream, and radiation therapy. The surgical methods include simple excision, physical destruction (curettage with electrodesiccation) and Mohs micrographic surgery.
The treatment of each skin cancer must be individualized, taking into consideration such factors as patient’s age, location of the cancer, type of cancer and whether or not the cancer has been treated previously. In some instances, more than one type of therapy may be appropriate. But in most cases, only one or two of the options are reasonable.
Mohs Micrographic Surgery
In the early 1940’s, Dr. Frederic Mohs, Professor of Surgery at the University of Wisconsin, developed a form of treatment for skin cancer which he called chemosurgery. (The word “Chemosurgery” is derived from the words “Chemical” and “Surgery.”) The technique has since come to be known as “Mohs Surgery” in honor of Dr. Mohs.
Mohs Surgery is a highly specialized treatment for the total removal of skin cancers, in which the microscope is used to determine the extent of the tumor and its location. The procedure has since been refined and improved upon, and today almost all cases are treated by the “fresh tissue” technique (which omits the chemical paste).
Mohs Micrographic Surgery allows for the selective removal of the skin cancer with the preservation of as much of the surrounding normal tissue as is possible. This is because of the complete systematic microscopic search for the “roots” of the skin cancer. Mohs Micrographic Surgery offers the highest chance for complete removal of the cancer while sparing the normal tissue. The cure rate for new skin cancers exceeds 97%.
There are two basic steps to each Mohs Micrographic Surgery stage. First, a thin layer of tissue is surgically excised from the base of the site. This layer is generally only 1-2 mm larger than the clinical tumor. Next, this tissue is processed in a unique manner and examined underneath the microscope. On the microscopic slides, our Fellowship trained Mohs surgeon examines the entire bottomsurface and outside edges of the tissue. (This differs from the “frozen sections” prepared in a hospital setting which, in fact, represent only a tiny sampling of the tumor margins.) If any tumor is seen during the microscopic examination, its location is established, and a thin layer of additional tissue is excised from the involved area. The microscopic examination is then repeated. The entire process is repeated until no tumor is found.
Mohs surgery is very useful and may be recommended for the following types of cancer:
- When the size or extent of the skin cancer cannot be defined easily.
- When the cancer is in a place, such as the nose, eyelids, lips or ears, where it is desirable to spare as much of the normal skin as possible.
- When the cancer returns after being treated.
- When the cancer is large.
- Complete removal of the tumor
- Reconstruction of the surgical wound so as to optimize the aesthetic result.
- Keep the surgical wound as small as possible given the size of the tumor.
During the pre-operative consultation will review your medical history and clinically assess the extent of your tumor. The tumor will be photographed to document its exact location. We will discuss the available reconstructive options and answer any questions you may have.
Before Mohs Micrographic Surgery
Get a good nights rest and eat a normal breakfast (unless your reconstruction is scheduled with a plastic surgeon and they have requested that you not eat prior to surgery). Take your usual medications, unless directed otherwise at the time of consultation. Should you be on an anticoagulant medication such as aspirin, plavix or, coumadin we request that you follow the instructions given to you at the time of consultation. Do not stop any of these medicines without the prior approval of your primary care physician or cardiologist. If you take aspirin or Advil type medications for pain or arthritis you may substitute Tylenol. Tylenol does not affect bleeding as both aspirin and Advil do.
If you have been advised in the past to take antibiotics before a surgical procedure, such as dental work, please adhere to the prescription instructions before your Mohs surgery appointment.
Shampoo your hair the night before surgery, as your wound and initial dressing may have to remain dry for 24 hours or longer. The length of time of the procedure varies depending on the size and location of the skin cancer and the type of reconstruction to be done. Although the average length of time is 2-4 hours, you should plan on spending much of the day in our office. We ask that you limit the number of people accompanying you to one other because of the limited space in our waiting room. There is time spent waiting for the layers to be processed, so bring a book or handiwork to keep busy. We also offer high speed wireless internet connectivity in our waiting room. You are welcome to bring your laptop computer enabled with wireless capability. (Wi-Fi not available at all locations)
The Day of Surgery
Appointments for surgery are scheduled throughout the day. It is a good idea to wear loose fitting clothing and avoid “pullover” clothing. Also, if the operative site is on the face, please do not wear make-up on or around the area.We will obtain your written consent for the procedure and photographs will be taken. If you have any additional questions, please feel free to ask them at this time.
The area surrounding the skin cancer will be cleansed with an anti-bacterial soap. The visible tumor will be marked and then we will then anesthetize (numb) the area of skin containing the cancer by a small local injection. This injection will probably be similar to the one you received for your biopsy. We will be as gentle as we can when administering this. It usually takes 15 minutes to anesthetize the involved area and surgically excise the tissue with a scalpel. After the tissue has been removed, it will be processed in our office laboratory.
Depending upon the amount of tissue removed, processing usually takes an additional 20-60+ minutes. Your wound will be bandaged, and you will move to the waiting room while the tissue is processed, stained, and examined by your surgeon. If the microscopic examination of the removed tissue reveals the presence of additional tumor, we will go back and remove more tissue. The Mohs technique allows us to precisely map out where the roots of the cancer remain. Most skin cancers are removed in 1-3 surgical stages. Rarely the “roots” of the tumor can extend far from the biopsy site and many layers may be needed to remove the cancer.
After the skin cancer has been completely removed, a decision is made on the best method for treating the wound created by the surgery. These methods include letting the wound heal by itself, closing the wound in a side to side fashion with stitches, closing the wound with a skin graft or a flap. In most cases, the best method is determined on an individual basis after the final defect is known. Most of the wound closures are performed in our office. However, other surgical specialists may be utilized for their unique skills if necessary. We individualize your treatment to achieve the best results.
When the reconstruction is completed by other surgical specialists, that reconstruction may take place on the same day or on a subsequent day. There is no harm in delaying the reconstruction for several days. If the reconstruction is to be extensive, that portion of the operation may require hospitalization. This is the exception rather than the rule as most wounds are repaired immediately in our office while the site is still anesthetized.
After Mohs Micrographic Surgery
Your surgical wound will require care during the weeks following surgery. Detailed written instructions will be provided. You should plan on wearing a bandage and avoiding strenuous physical activity for at least a week. Stitches are removed from 7-28 days after surgery depending on the type of reconstruction performed. Most of our patients report minimal pain which responds readily to Tylenol. You may experience a sensation of tightness across the area of surgery. Skin cancers frequently involve nerves and months may pass before your skin sensation returns to normal. In rare instances, the numbness may be permanent. You may also experience itching after your wound has healed. Complete healing of the surgical scar takes place over 12 months. Especially during the first few months, the site may feel “thick,” swollen, or lumpy, and there may be some redness.
A follow-up period is necessary after the wound has healed. You will be asked to return so we can access how you are healing following the procedure. Studies have also shown that once you develop a skin cancer, there is a strong possibility of developing other skin cancers in the future. Should you notice any suspicious areas, it is best to check with your dermatologist for a complete skin evaluation. You are reminded to return to your dermatologist on a frequent basis for continued surveillance of your skin.
Sometimes the buried sutures may work their way up to the surface of the skin creating crusted areas along the suture line. This can occur anytime from 2 weeks to a few months post-op. Should this occur, please call us for an appointment as this can be easily addressed by us.
Risks of Mohs Microscopic Surgery
Because each patient is unique, it is impossible to discuss all the possible complications and risks in this format. The usual risks are discussed below. Your Mohs surgeon will discuss any additional problems associated with your particular case. Please understand that these occurrences are the exception and not the rule.
- The defect created by the removal of the skin cancer may be larger than anticipated. There is no way to predict prior to surgery the exact size of the final defect.
- There will be a scar at the site of the removal.We will make every effort to obtain optimal cosmetic results, but our primary goal is to remove the entire tumor. Again, Mohs surgerywill leave youwith the smallest wound thus creating the best opportunity for optimal cosmetic results.
- There may be poor wound healing. At times, despite our best efforts, for various reasons (such as bleeding poor physical condition, smoking, diabetes, or other diseases), healing is slow or the wound may reopen. Flaps and grafts utilized to repair the defect may at times fail. Under these circumstances, the wound will usually be left to heal on its own.
- There may be a loss of motor (muscle) or sensory (feeling) nerve function. Rarely, the tumor invades nerve fibers. When this is the case, the nerves must be removed along with the tumor. Prior to your surgery, the doctor will discuss with you any major nerves which might be near your tumor.
- Since the tumor may be near or involving a vital structure such as the eyelids, nose or lips, portions of the structure may have to be removed. This can result in functional or cosmetic deformities.
- There may be excessive bleeding from the wound. Such bleeding can usually be controlled during surgery. There may also be bleeding after surgery, bleeding under a sutured graft or flap may inhibit wound healing.
- There may be an adverse reaction to medications used. We will carefully screen you for any history of problems with medications; however, new reactions to medications may occur.
- There is a small chance that your tumor may regrow after surgery. Previously treated tumors and large, longstanding tumors have the greatest chance for recurrence.
- Rarely, wounds become infected and require antibiotic treatment. If you are at particular risk for infection, you may be given an antibiotic prior to surgery.
- In some instances the organism causing the infection can be resistant to standard antibiotics necessitating consultation with an infectious disease specialist and intravenous medication.
First, the area involved with cancer is numbed with the injection of a local anesthetic to eliminate pain. This is usually the only painful part of the procedure. We use a number of techniques to minimize the pain of administering local anesthesia.
Using a sharp curved instrument, the cancerous lesion is carefully scraped so that the margins of the lesion are well defined. During this procedure you may feel some pressure but should not feel any pain.
A 1 to 3mm margin of tissue is marked beyond the scraped area.
Then the lesion is removed along with the thin tissue margin, which surrounds the lesion on the sides and underneath.
The tissue is then carefully divided into pieces and their edges marked and color coded with special dyes.
A careful "map" is made of the treatment area corresponding to the color code used on the removed tissue.
The tissue is taken to our laboratory where it is rapidly frozen, cut into thin sections, placed on microscope slides, and stained.
Using the microscope, the surgeon determines whether any tumor persists. If an edge of the wound still contains tumor, it is noted on your patient map.