What is Mohs micrographic surgery?
Mohs micrographic surgery – also known as Mohs or Mohs surgery – is a specialised type of skin cancer surgery that was developed by Dr Frederick Mohs in the late 1930s.
Southderm, southern Sydney’s leading skin cancer clinic specialises in Mohs micrographic surgery. Mohs micrographic surgery differs from other types of skin cancer removal, in that it uses a microscope to inspect the skin cancer and guide its removal. Multiple, thin layers of tissue are carefully removed, and each layer is inspected under the microscope to check for the presence of cancer cells. Layers of tissue are removed and examined one at a time until no cancer cells are present. Because only tissue containing cancer cells is removed, as much normal skin as possible is saved. In this way, Mohs micrographic surgery allows the skin cancer to be completely removed with a high degree of accuracy, while reducing the loss of healthy tissue. This technique has excellent overall cure rates and cosmetic results.
In Australia, Mohs micrographic surgery is performed by specially trained and accredited Mohs surgeons. To become a Mohs surgeon, a dermatologist must undertake a post-specialist qualification fellowship, during which time they receive in-depth experience and training in the Mohs technique. At SouthDerm we have three qualified Mohs specialist dermatologists.
In addition to the Mohs specialist, a team of specialised trained healthcare personnel are involved in your care, including trained doctors and nurses, pathology technicians and laboratory staff.
What are the benefits of Mohs micrographic surgery?
Mohs micrographic surgery allows the skin cancer to be completely removed while reducing the loss of normal surrounding tissue. Because it is such a precise technique, there is less scarring.
The Mohs technique has a higher cure rate for skin cancer removal than any other technique currently available – more than 95% of patients treated using Mohs micrographic surgery are cured of skin cancer. (As with most surgery, a 100% cure rate can never be guaranteed.)
This technique also allows the cancer cells to be identified and treated at the same time. Mohs micrographic surgery can be used on a variety of skin cancers.
When is Mohs micrographic surgery performed?
There are several reasons why Mohs micrographic surgery may be recommended by your dermatologist. For example:
- The skin cancer is in difficult position
- It is important to preserve appearance (e.g. skin cancers on the face)
- The skin cancer has returned after previous treatment
- It is hard to work out the extent or size of the skin cancer
- The cancer is an aggressive type that grows quickly
- The skin cancer is very large
What does Mohs micrographic surgery involve?
Mohs micrographic surgery is done using a local anaesthetic to numb the area, so that you are awake during the entire procedure. Antibiotics and pain killers may also be administered. The skin cancer is removed gradually, a layer at a time, until no further cancer cells are left. The total procedure is usually done over several hours.
What are Mohs “stages”
A “stage” is the term used to describe the removal of each layer of the skin cancer.
To begin with, the visible skin cancer is identified, measured and marked. Once the skin is completely numb, a special instrument is used to gently remove a layer of tissue. This is the first stage. Once a layer of tissue has been removed, a map or drawing of the tissue and its location is made, and the tissue layer is labelled and colour-coded to show where it came from. The layer is then prepared and put on a slide, which is examined under the microscope.
If the specialist dermatologist sees evidence of cancer cells under the microscope, another layer of skin is removed – this is a second stage. This layer is then examined for additional cancer cells. If cancer cells can still be seen under the microscope, another layer of skin is removed and examined – the third stage. The process is continued layer-by-layer until the cancer is completely removed.
Most skin cancers require several stages for complete removal.
What happens in between each Mohs stage?
Between each stage of the procedure, any bleeding is controlled and a bandage is applied to the area while the layers are being examined under the microscope. You will also be given additional local anaesthetic and pain killers as needed for your comfort. You are generally allowed to eat and drink in between each stage if you wish.
What happens after the procedure?
Once the Mohs specialist dermatologist is confident the tumour has been completely removed, you will go back to the operating theatre so that the wound can be closed. You may need stitches, a skin graft or flap to close the wound. Occasionally the wound closure is done by a plastic surgeon.
After the procedure you may require additional medication such as antibiotics or pain killers. You will be booked in for a follow-up appointment for review and removal of any stitches.
What are the risks of Mohs micrographic surgery?
Generally, the risks of Mohs micrographic surgery are similar to other types of surgery and may include:
- Recurrence of tumour
- Nerve damage
Where can I get more information?
Further information about Mohs micrographic surgery is available from the following places:
- The Australasian College of Dermatologists: www.dermcoll.edu.au
- The American College of Mohs Surgery (ACMS): www.mohscollege.org
- Your SouthDerm specialist dermatologist
All medical and skin cancer treatments are carried out in our southern Sydney, Kogarah, skin cancer and cosmetic surgery clinic.