Oxford Day Surgery and Dermatology specialises in this technique which is standard practice in America and Australia.
What is Mohs surgery?
In the early 1940's, Dr Frederick Mohs, Professor of Surgery at the University of Wisconsin, developed a new treatment for skin cancer.
The technique has since come to be known as Mohs surgery. Mohs Surgery is a highly specialised treatment for the total removal of skin cancers, in which the microscope is used to determine the extent of the tumour and its location. It is also known as microscopically controlled serial excision (MCSE).
The major advantages of Mohs' Surgery are:
• The tumour is completely removed with minimal loss of normal skin
• The rate of cure is approximately 98%, which is substantially higher than any other method of treatment
Treatment is performed under local anaesthetic. In selected cases sedation may be used, either through oral medication or very rarely by injection. The visible tumour, together with a small margin of visually normal skin is removed; this is known as a "stage”. Bleeding is controlled and a pressure dressing is then applied, and the patient is asked to wait in a comfortable private recovery area while the slides are being processed.
The removed tissue is carefully divided into pieces that will sit on a microscopic slide. The edges are then marked with specially coloured dyes; a careful map is made of the tissue removed and the tissue is frozen by the technician. Thin slices can then be made from the frozen tissue and examined microscopically by the doctor who is now able to visualize any residual cancer. If cancer cells remain, another layer of tissue is then surgically removed, and the procedure is repeated until no cancer cells remain. This process preserves as much normal, healthy, surrounding skin as possible.
Duration of Surgery
The removal of each layer of tissue (stage) takes approximately one hour. Only 10 to 20 minutes of that time is spent in the actual surgical procedure, the remaining time being required for slide preparation and interpretation. It may take two or three stages (occasionally more) to complete the surgery. The procedure will usually be completed within 1 to 4 hours, depending on the extent of the cancer and the difficulty of the area being treated.
Rate of Cure
The percentage of success is generally very high with this procedure, ranging from 97% to 99%, even if other forms of treatment have failed. However, no one can guarantee a 100% cure.
When is Mohs surgery recommended?
Mohs surgery is ideal in the following situations:
• A skin cancer has recurred after previous treatment
• It is in a difficult site such on the face, especially around the nose, eyes, lips and ears
• It is difficult to see the margins of the skin cancer
• The skin cancer has an aggressive pattern of growth
What are the benefits?
This process ensures that all cancerous cells are removed, and as much healthy skin as possible is preserved. Mohs surgery offers the highest chance of cure with the initial treatment.
Why is it important that it is all removed?
If cancer cells are left behind at the time of initial surgery, then there is a very high chance that the cancer will reoccur. Frequently when this happens it grows for a substantial period of time underneath the scar and may not be visible on the skin for many years. This makes subsequent treatment much more extensive and difficult.
What are the risks?
Like all surgery, Mohs surgery can cause bleeding, bruising and swelling. In most cases, these are easy to control.
Uncommonly, infection may occur following Mohs surgery. This may be indicated by increasing redness surrounding the wound, associated with increasing pain and tenderness. The wound may begin to discharge fluid or pus and feel hot to touch. If you notice any of these symptoms, contact our office immediately.
Nerve damage associated with Mohs surgery is usually temporary however in some cases can be permanent if the cancer is extensive and the nerve is involved. Scarring from surgery is usually limited and settles very well. Flaps and graphs take more time to heal but improve significantly with time.
Our doctors will discuss these risks with you, and the steps that can be taken to minimise and control them.
What happens after the tumour has been removed?
After Mohs Surgery, you will be left with a surgical wound. This wound will be dealt with in one of several ways. The options will be discussed with you in order to provide the best possible functional and cosmetic results.
The possibilities include:
(1) Direct closure of the wound, or part of the wound, with stitches
(2) Various skin closures, such as grafts and flaps, or reconstruction procedures
(3) Healing by spontaneous granulation
(4) Referral for reconstruction or radiotherapy
Upon completion of the surgery, we will recommend which of these choices will be best for your individual case.
What happens if the wound is closed with stitches?
The majority of wounds are closed with stitches. This involves some adjustment of the wound so the edges can be stitched together. The procedure speeds healing time and offers a good cosmetic result. In many cases, the scar can be hidden in a facial line or wrinkle line.
With a flap a larger wound needs to be created temporarily to allow movement of skin. This leads to more stitches than you may have anticipated. The final cosmetic outcome is usually very good. With grafts a second wound is created to obtain skin (from a donor site). This is usually taken at a non cosmetic site to minimise scarring.
The stitches will remain in place for either five to seven days or for two weeks, depending on the location of the lesion. While the stitches are in, you should refrain from activities that might pull on the sutures. You will be given detailed wound care instructions on the day.
What is Spontaneous Granulation?
Healing by spontaneous granulation involves letting the wound heal by itself. Experience has taught us that there are certain areas of the body where nature will heal a wound as nicely as any further surgical procedure. If the wound is allowed to granulate in, it usually heals in four to eight weeks and requires daily dressing changes.
What happens after surgery?
In the week or so after surgery you will come back to Oxford for wound care. This will be scheduled according to your specialist’s advice. Once this initial stage is over and you are back to normal, your surgeon will meet with you in clinic. This visit is to check the scar is settling, to answer any questions you have and to check that that all is going well prior to discharging you back to your referring doctor for ongoing care.
You can find more information on Mohs Surgery in Information for Patients.