Mohs Micrographic Surgery
What is Mohs Micrographic Surgery?
Mohs Micrographic surgery (also called Mohs surgery) is a highly technical, micro surgical technique used to treat skin cancer. It is the most advanced and effective treatment available for skin cancer.
Mohs Micrographic surgery is now seen as the single most effective technique for removing Basal Cell Carcinoma (BCC) and Squamous Cell Carcinoma (SCC) - the two most common forms of skin cancer. Cure rates for BCC and SCC are 99% higher with Mohs surgery than with standard excision or any other accepted method. (1.)
The technique is named after Dr Frederick Mohs, a professor in surgery in the USA during the 1930's.
During Mohs Micrographic surgery, a specially-trained surgeon progressively removes microscopic horizontal layers of the patient's skin. That tissue is then immediately processed and examined in a pathology lab to determine whether the skin cancer has been completely removed. If not, the surgeon then removes that tiny section remaining, and the pathology process is repeated.
The technique allows surgeons to verify that all cancer cells have been removed at the time of surgery. This increases the chance of a cure and reduces the need for additional treatments or surgery.
The Skin & Cancer Foundation Inc also uses Mohs Micrographic surgery to remove melanomas.
Mohs Micrographic surgery can only be carried out by accredited Mohs Micrographic Surgeons. There are several Mohs surgeons working at the Skin & Cancer Foundation Inc.
They are specially trained dermatologists who have undertaken a minimum of an extra 1-2 years approved Mohs surgery training. Approved Mohs Micrographic Surgeons are both Fellows of the Australasian College of Dermatologists (FACD) and accredited Mohs surgeons.
They are also required to undertake regular assurance programs in diagnostic dermatopathology, run by the Royal Australasian College of Pathology, and the rigorous standards applied by the Australasian College of Dermatologists.
A list of accredited Australian Mohs Micrographic Surgeons can be seen here.
Why this technique?
The virtue of Mohs Micrographic surgery is that it removes the skin cancer very effectively, while minimising damage to surrounding healthy tissue.
Mohs surgery is micrographically controlled, therefore provides extremely precise removal of cancerous tissue, while healthy tissue is spared. It is particularly advantageous in areas such as the eyelids, nose and lips.
With traditional surgical removal of skin cancers, only about 1-3% of the tumour margins are examined, which, when compared to Mohs, increases the chances that a small tumour cluster will be missed and left behind. Mohs allows for examination of 100% of the tumour thereby minimising the chance of tumour cells being left behind.
Mohs surgery is performed under local anaesthetic as a day patient procedure.
The visible tumour is surgically removed in the first stage (similar to a biopsy), and stained in preparation for processing in our onsite pathology laboratory. A dressing is then applied and the patient then waits comfortably in the recovery suite.
The stained specimen is frozen by the pathology scientist and then divided multiple times and mounted onto slides. These are then examined microscopically by the Mohs surgeon and it is then determined if there is any residual cancer. If cancer cells remain, another stage of surgery is carried out. The procedure is repeated until no cancer cells remain. This process preserves as much normal, healthy surrounding skin as possible.
The approximate time for each stage is 1-2 hours. Usually 14-20 minutes of this time is spent in the procedure room. The remaining time is required for preparation, examination and interpretation of slides.
After Mohs surgery, the patient will be left with a surgical wound. The repair option chosen aims to give the best possible cosmetic and functional result. The wound will be repaired in one of several ways including direct closure, flaps, grafts or granulation.
Direct closer is a common type of repair and involves stitching the edges of the wound directly together.
Flap repairs involve moving nearby skin to fill the wound. This leads to more stitches than you may have anticipated.
Graft repairs involve taking skin from another area of the body (donor site). This is usually from a non-cosmetic site to minimise scarring. The donor skin is then grafted/sewn to the wound with stitches.
Granulation involves letting the wound heal by itself like a graze. If the wound is allowed to granulate it usually heals in 8-10 weeks. Daily dressing changes are required.
Am I a good candidate for Mohs?
Mohs is widely used for the surgical removal of the most common types of skin cancers (BCCs and SCCs). It is not currently used to remove non-cancerous growths. Mohs surgery is especially useful for skin cancers that:
- Have a high risk of recurrence or that have recurred after previous treatment
- Are located in an area where you want to preserve as much healthy tissue as possible
- Have borders that are hard to define
- Are large or aggressive
Even if Mohs is the most appropriate treatment of skin cancer, some patients may not be good candidates for Mohs if they are unable to tolerate local anaesthesia, have extreme anxiety, have a surgical phobia, or are in very poor health.
Which areas are treatable using Mohs?
Mohs is used primarily for treatment of head and neck basal and squamous cell cancers. It is particularly useful for skin cancers in difficult areas such as nose, eyelids, lips and ears.
Mohs is also used on hands and feet, where there is not a lot of extra tissue for large surgical removals.
While it is more often used on the face, neck, hands and feet, any area of the body may be treated using Mohs surgery.
What are the possible complications of Mohs?
While Mohs is overall a very safe and effective surgical treatment, like any surgery or procedure there are some possible uncommon complications. Most patients tolerate Mohs surgery very well without any complications. After a few months, most patients will have only a very fine, barely visible scar.
As with all surgeries complication may arise. A list of these complications include:
- Incomplete removal of cancer
- Pain afterwards
Your surgeon will discuss associated risks and complications. Patients should speak to their doctor about any concerns or questions they may have.
A dressing will be applied after surgery to help reduce bleeding. You will be given verbal and written wound care instructions and information on what to do in the event of any complications.
You may need time off work and exercise regimes may need to be ceased temporarily. You should discuss any concerns with medical staff.
You will be required to return one week post-surgery for removal of sutures (stitches) and wound review. A follow up appointment at the Foundation will also be booked. After the wound has healed you will be referred back to your regular doctor for ongoing surveillance.
Download the Mohs Surgery brochure or view more brochures on our Brochures page.
1. Mohs Surgery, Shang I Brian Jiang, MD Clinical Professor of Medicine and Dermatology, Director, Dermatologic and Mohs Micrographic Surgery, Program Director, UCSD Dermatologic and Mohs Surgery Fellowship, University of California School of Medicine, San Diego. Shang I Brian Jiang, MD is a member of the following medical societies: American Academy of Dermatology, American College of Mohs Surgery, American Society for Dermatologic Surgery, Association of Professors of Dermatology; Medscape, see Tables at http://emedicine.medscape.com/article/2212475. Accessed 31 March 2017.
2. Images where acknowledged, and with thanks, sourced from http://www.mohssurgery.com.