Mohs Surgery

MOHS SURGERY offers one of the the highest chance of cure of some skin cancers, particularly Basal Cell Carcinomas (BCCs) while ensuring the amount of skin removed is kept to a minimum.


In the 1930’s, Dr Frederick Mohs, from Wisconsin USA, first conceptualized and then developed his treatment for skin cancer. The technique has since come to be known as “Mohs Surgery” as due recognition for Dr Mohs’ outstanding contribution to the field of skin cancer treatment.

What is Mohs Surgery?

Mohs Surgery is a highly specialized treatment for the total removal of skin cancers. The visible component of the cancer is surgically excised and then subjected to microscopic analysis whilst the patient waits. Any residual areas still positive for cancer are identified and subsequently removed. This process continues until all the cancer cells are cleared. Mohs surgery allows cancer cells to be fully and accurately tracked without guesswork until they are completely removed.

Why is it important that all cancerous cells be removed?

If cancer cells are left behind at the time of initial surgery, there is a very high chance that the cancer will recur. When this happens it will frequently grow for a substantial period of time hidden under the previous surgical scar. This makes the subsequent treatment of the recurrent cancer much more extensive and difficult.

When is Mohs Surgery recommended?

Mohs surgery is ideal when a skin cancer

  • Is present in a difficult site, where the conservation of as much normal tissue is critical as on the face and especially around the nose, eyes, lips and ears.

  • Has recurred after previous treatment(s).

  • Has been incompletely excised after initial surgery.

  • Is discovered to be certain microscopic type on initial biopsy.

What are the advantages of Mohs Surgery?

  • It ensures that all cancer cells are removed.

  • As much healthy skin as possible is preserved.

  • The cure rates are  higher than with any other mode of treatment.

The Mohs Surgery procedure:

"First stage"

The area to be treated is first numbed with local anaesthetic and the visible cancer is removed. A dressing is applied to the wound and the patient returns to a waiting area.

Tissue mapping

While the patient waits, the removed tissue is precisely oriented and then divided into small sections and the edges marked with colored dye and a tissue map is drawn. The tissue is then handed to the laboratory technician.

Tissue processing and examination

The tissue is frozen and cut by the technicians, then mounted on to microscope slides and stained using highly specialized chemicals to identify the different cell types. The doctor then examines the tissue under the microscope to see whether any residual cancer cells can be identified.

Further surgery ("second and or subsequent stages")

If there is any residual cancer, the wound is re-anaesthetised and further tissue corresponding precisely to the area of positivity is excised and again microscopically checked. This process continues until the Mohs Surgeon is satisfied that no cancerous cells remain.

Wound repair

Once the cancer is shown to be completely removed the patient wound is repaired.
There are many ways in which the post Mohs Surgery wound can be repaired including

  • Granulation (“healing by itself”)

  • Simple side to side closure

  • Skin flaps where adjacent skin is utilized to cover the defect.

  • Skin graft

  • Combinations of the above

  • Occasionally the wound may be repaired by another specialist if the cancer involves a site requiring special expertise.


  • One the wound has been repaired the patient is discharged home.

  • The patient will usually return at one week for removal of stitches and thereafter on an as required basis.

Final outcome

Almost certainly following Mohs Surgery the cancer in that site will be cured. The final functional and cosmetic outcome is usually excellent.

Who performs Mohs Surgery?

Dermatologists who have undertaken post specialist Fellowship training in Mohs Surgery and who are officially sanctioned by the American College of Mohs Surgery and or the Australasian College of Dermatologists.
Any surgical or invasive procedure carries risks, please discuss this with your Specialist at the time of your appointment.

view all

Fact Sheet Library

  • Basal Cell Carcinoma (BCC)

    BCCs are the most commonly seen form of skin cancer.

    view fact sheet
  • Squamous Cell Carcinoma (SCC)

    The second most common skin cancer, it is often rapidly growing and may spread to other parts of the...

    view fact sheet