MOHS Micrographic Surgery
Mohs surgery is an advanced surgical technique used for the treatment of skin cancers. The procedure offers the highest chance of cure from any treatment available, while conserving healthy tissue around the skin cancer. A Mohs surgeon is a qualified dermatologist who has undergone further sub-specialised training in pathology and surgery. The Australasian College of Dermatologists provides a list of accredited Mohs surgeons in Queensland.
What is Mohs surgery?
Mohs surgery is a specialised treatment for the total removal of skin cancers. Pathology is checked by your surgeon with a microscope on the day of surgery, to confirm the cancer is ‘all out’, prior to surgical reconstruction/repair.
A Mohs surgeon is a specialist dermatologist, who has undergone further training to become a Mohs surgeon, trained in pathology as well as complex surgical reconstruction (flaps/grafts). Mohs surgery is available in only a few centres in Queensland.
How is Mohs surgery different to conventional/routine excision of skin cancers?
Mohs surgery is ‘tissue sparing’. Only the cancer is removed, without an additional margin of ‘normal skin’ being taken around the cancer. This preserves all healthy skin, keeps the surgery as small as possible, and thus minimises scarring.
The cure rate of Mohs surgery is superior (99%), compared to conventional (>/= 95%) excision. This is achieved by comprehensive margin assessment. Mohs surgery assesses all of the edges of what has been removed, in totality. Normal pathology only samples the edges. This circumferential margin assessment allows your surgeon to make a precise map of the tumour shape, and to take additional tissue from specific required areas only if necessary.
With conventional or standard excisions, results become available in the days after surgery. If pathology shows an incomplete excision, repeat surgery is required. Any repeat surgery is always more complicated than if the cancer has been fully removed in the first instance. By contrast, part of the Mohs surgery procedure is confirming the cancer is all gone, before the wound is stitched closed. The procedure is therefore confirmed as complete all in one day.
Surgical repair
Once the cancer is confirmed as fully removed, the surgical area is repaired. The ‘best’ repair is determined by your surgeon’s assessment of the individual nature of your surgical area, and your individual priorities. A standard side-to-side repair is favoured when appropriate; however, if the skin is too tight to achieve this, then a flap or graft is preferred, each having its own set of advantages and limitations.
Possible surgical repairs:
Direct side-to-side closure
Stitched together in a straight line
Flap
This involves loosening adjacent skin, to pull or push this across into the surgical area. Flaps come in various shapes and sizes and are always designed for the individual, based on what will sit best (and thus look best) in their tissues.
Graft
This is a piece of skin taken from elsewhere on your body and stitched over the area like a patch. Grafts may be full thickness or partial thickness – your surgeon will explain why a graft is being used if required.
Secondary intention healing
This involves allowing the body to heal itself and is only an option in certain body sites. Disadvantages include slow healing; however, advantages including contraction and reduced size of the scar.
General information
The area involved is numbed with long-lasting local anaesthetic at the beginning of the Mohs procedure. Your numbing is checked, and ‘topped up’ during the day if required, so that you remain comfortable.
After the initial excision, it takes approximately 2 hours for the microscope slides to be prepared. If your surgeon sees your cancer is fully removed, the wound is then repaired. If your surgeon sees cancer at the edges of what has been removed, more tissue is taken, and more microscope slides are made. Sometimes cancers are significantly bigger than what can be seen on the skin surface. Several surgical ‘stages’ may then be required to confirm the cancer is all out; however 1-2 stages is more commonly all that is necessary.
Occasionally, cancers aren’t able to be fully removed with surgery, and additional treatment with radiotherapy may be recommended. This also applies when skin cancers are seen to have spread in to the nerves (called perineural invasion). Your surgeon will discuss this with you, in the rare event that this is observed on your pathology.
The pathology processing means that Mohs surgery takes some hours. Allow the whole day, though often only half a day proves required. Bring a book/ipad/laptop along to fill the time.
Unless advised to fast (for combined procedures with plastic surgeons and oculoplastic surgeons, where an anaesthetist is involved), you can eat and drink normally, and take all your usual medications. Unless advised by another involved surgeon, do NOT stop any blood thinning medications (eg xarelto, plavix, aspirin, eliquis, warfarin).
Please use an antibacterial body wash (eg phisohex) all over your body (avoiding your eyes) the day prior to surgery. This is proven to reduce the chance of a wound infection following surgery.
Mohs surgery is performed in an operating theatre at Westside Private Hospital. You should not drive yourself after the surgery. Relatives or friends cannot wait with you during the surgery, but will be advised when it is time to come to collect you.
After surgery
Woundcare
Our nursing team will advise on woundcare for your wound(s). Grafts must be kept dry for a week; however, most wounds only require 24-48 hours of dressings, and can be wet in the shower from 48 hours onwards.
Downtime
You should arrange for at least two days off work (the day of treatment, and one day off afterwards), but may need longer, depending on the extent of your surgery. Any surgery around the upper face or scalp can result in swollen bruised eyes.
Lower Legs Surgeries
Require special care, and can be slow to heal. Compression stocks, and resting/elevating the operative leg are important. Provided you feel stable using crutches, these are also helpful for the first 1-2 weeks. Going out for a walk, or doing any lower limb exercise, should be avoided for 2 weeks.
Please request a medical certificate in advance, if you need one.
Exercise
Plan to avoid any strenuous activity, that would cause you to sweat, for at least 5-7 days. Avoid swimming for two weeks.
Pain
Usually this is mild to moderate at most, and easily managed with simple pain measures at home, such as ice packs and/or paracetamol and/or ibuprofen.
Bleeding
If you notice blood seeping into or through your dressing, please remove the dressing, and use a handful of clean tissues or cotton balls to apply pressure for 20 minutes. If bleeding persists, please contact Q Dermatology (or your surgeon directly if out of hours).
Swelling and Bruising
This is common following surgery, especially on the face. Ice packs, and sleeping with your head elevated on a couple of pillows, may help.
Infection
Any surgical wound can become infected. Please contact Q Dermatology if you have any concern that your wound may be infected – eg increasing redness/pain/ooze.
Numbness
Surgical sites are often numb, as the small nerve endings in the skin are interrupted by surgical excisions. This improves considerably for up to 12 months after surgery; however sometimes numbness is permanent.
Scarring
All surgery results in a scar. During the healing process, facial scars in particular are often red and bumpy. The internal stitches, under the wound surface, make the wound feel lumpy for 12 weeks, while they dissolve. Scars generally soften considerably over the first few weeks and months. Healing is gradual: a wound is 50% the strength of normal skin at 4 wks, and 100% strength at 12 months. During that time, the redness fades, and the scarline becomes finer. Laser can be used to improve the redness more quickly, and is performed every few weeks for three sessions. Please discuss with a member of our team if you would like to consider laser treatment of your scar.
Follow-up
External stitches are removed anywhere between 5 and 14 days, depending on the area of your face or body involved. Please call for sooner review at Q Dermatology, however, if you have any queries regarding your wounds or dressings.
Continued regular skin checks remain important after surgery, including of the area operated on with Mohs surgery. Mohs surgery has a 99% cure rate; however, this is lower for already complicated, recurrent, or extensive tumours. If you are ever concerned regarding changes around your surgical area, even if many years down the track, please call Q Dermatology to arrange review.