Mohs micrographic surgery was developed in the 1930s by Dr Frederick Mohs.
It has been refined over the years. It is a specialised method of removing skin
cancer and aims to achieve the highest likelihood of cure but potentially
remove the minimum amount of skin. The procedure involves surgically removing
skin cancer layer-by-layer analysing each layer of tissue under a microscope
until healthy cancer-free tissue around the tumour is reached, called clear margins.
During the first layer we will mark out the visible part of the tumor
with a pen and then inject the area around the tumour with a local anaesthetic
this numbs the area so you'll not feel any pain during surgery but will remain awake.
We may also use an anaesthetic eyedrops if the tumour is near your eye.
The tumour is then cut out or scraped away, known as curettage, and we then
remove a very small margin, usually one to two millimetres, by scoring around the
pen line with a scalpel and then cut out the tumour in one even piece.
This is known as a layer.
The surgeon then stains the tissue using special ink so we know
exactly which way round it sat on the skin.
The nurse will then place a secure dressing over the wound and you'll be
asked to sit back in the waiting room.
The marked issue is then sent to the lab where it will be frozen into a block, sliced
into fine horizontal sections, and put onto microscope slides.
The surgeon then examines them under the microscope. If the tissue contains cancer cells,
we will remove and examine another layer of tissue in exactly the same way. We repeat
this process until the surgeon examines tissue that contains no cancer cells.
When this happens we know we've removed all the cancerous cells from that site.
Mohs surgery is unique and so effective because we can evaluate all tissue that
is removed and the surgeon can map any tumour to the exact location on the patient's skin.
This allows all the deepest parts of the tumour to be found accurately and removed
After we have removed the skin cancer with mohs surgery we may carry out reconstruction.
Reconstruction means fixing the wound that is left after the surgery.
We normally do this on the same day as the mohs, but we may need to do it
on another day.
There are various options for reconstruction these include allowing
the wound to heal by itself over a period of weeks,
this is safe and can result in a very good appearance but does require care of
the wound and dressing changes in the early stages. We may be able to pull the
edges of the wound directly together with stitches or alternatively we may be
able to move or stretch the skin and tissue near the wound to fill it up.
This is known as a flap repair. This may result in a longer or unusual shaped scar
but the final result is often very good. We may dettach skin from one area, such as
behind the ear and place this over the wound stitch it into place.
This is known as a graft. There may be more than one option for reconstruction
and we will discuss this with you to give you not only the best cosmetic
result but also the most practical one for your particular circumstances.
Shared decision-making is very important with this issue and it can help if you're
involved by discussing how you'd prefer to repair the wound.
When you cut the skin
there will always be some type of scar, some people heal more easily than others.
Some scars are more noticeable depending on the location and skin type but we
will always aim to ensure the best cosmetic result possible.
Depending on circumstances, you may have your wound repaired at another hospital or with
another team such as plastic surgery. In this case you would have a secure
dressing in place to go home with until your reconstruction date.
Mohs micrographic surgery has been recommended to you because your cancer
is in an area where we want to reduce the amount of healthy tissue removed
such as on your eyelids, your nose, your ears, or your lips. It's also recommended
if your cancer has been previously treated but has now returned.
Other surgical techniques can be used to remove skin tumours but this relies on
the surgeon being able to see the edge of the tumour clearly with the naked eye
and that tumour may be bigger or smaller than the surgeon thinks.
This can sometimes lead to a larger wound and scar if too much healthy tissue is removed,
but more concerning is that it could also lead to too little tissue being
removed and the cancer returning. The other techniques that are available
include, traditional surgical excision whereby the tumour is excised with a four
to six millimetre rim of normal tissue around it and the wound is close, all in one session.
A quick procedure is scraping and burning of the tumour called curettage and cautery.
Neither of these techniques offer as high a cure rate as mohs surgery and it's
not known until one to two weeks afterwards whether all of the tumour would have been removed.
They also may cause a larger than necessary scar.
A non-surgical option for treatment is radiotherapy
this uses high-energy x-rays or similar rays to treat cancer. It damages your
body cells in the treatment area, killing the cancer cells but allowing your normal
cells to recover. Its side effects such as redness and crusting are generally
isolated to the area you're havingtreated.
Before surgery you'll have an opportunity to speak to the nurse
to discuss the procedure in detail and ask any questions.
This may happen face to face if you are coming to the hospital for consultation or
over the phone if you do not need to attend a consultation before your surgery.
This is an opportunity to ask about what the procedure entails but
also for the nurse to discuss any other health issues you may have and whether
or not you take any medication.
On the day of surgery it's common for people to feel nervous.
The nursing staff will ensure that you feel comfortable and well prepared
before entering the procedure. You're allowed to eat and drink throughout the
day as the procedure is performed under a local anaesthetic.
We encourage you to bring lunch with you
as you'll be asked to stay in the unit until you're ready to go home.
You'll not spend long in the theatre itself, around 20 or 30 minutes depending
on the site and size of the lesion. The rest of the time you'll be sitting in the waiting room.
It can take up to two hours to get the results back.
We also encourage you to come with a friend or family member as you may be on the unit for the entire day.
After your procedure you have a pressure dressing in place
this is to ensure that the wound is well covered to prevent bruising, swelling and bleeding.
The nurse will go through any necessary wound care instructions and also give you written information.
Most patients are medically fit to travel after the procedure,
however if you feel unwell or tired it's best to be accompanied and to avoid public transport where possible.
If there are any concerns when you go home you'll be given a number to phone that puts you through to a nurse.
If you have a wound repaired with us we will generally ask you to come back in a week's time so
that we can look at the wound and remove any stitches.