Mohs Micrographic Surgery - The Skin Surgery Centre

What is Mohs Microscopic Surgery?

Most effective and advanced

treatment for skin cancer today

The term “Mohs” comes from Dr. Frederic Mohs. He was a surgeon at the University of Wisconsin. He created this technique in the 1930s. The technique has undergone many refinements and has come to be known as “Mohs micrographic surgery” or simply “Mohs surgery” in honor of Dr. Mohs

How does it work?

Step 1

The roots of a skin cancer may extend beyond the visible portion of a tumour. If these roots are not removed, the cancer will recur.

Step 2

The visible portion of the tumour is surgically removed

Step 3

A layer of skin is removed and divided into sections. The ACMS surgeon then colour-codes each of these sections with dyes and makes reference marks on the skin to show the source of these sections. A map of the surgical site is then drawn.

Step 4

The undersurface and edges of each section are microscopically examined for evidence of remaining cancer.

Step 5

When the surgeon observes cancer cells through a microscope, they note their location on a map. The surgeon then proceeds to remove additional skin only from the areas where the cancer cells are present. The removal process stops when there is no longer any evidence of cancer remaining in the surgical site.

Why Mohs?

Mohs micrographic surgery is the most effective and advanced treatment for skin cancer today. It offers the highest potential for cure – even if the skin cancer has been previously treated by another method.

Mohs surgery, created in the 1930s, is now the best treatment for many types of skin cancer. It is advanced, precise, and effective. With Mohs surgery, doctors can accurately find and remove a tumor without harming the nearby healthy tissue.

The Mohs procedure removes skin cancer layer by layer. It examines under a microscope until it finds healthy tissue around the tumor. Doctors call this healthy tissue clear margins.

Mohs surgery, performed by specially trained surgeons, has the highest success rate for skin cancer treatments, reaching up to 99%. This includes skills in cancer removal and reconstruction.

Benefits of Mohs

Mohs surgery is unique and so effective because of the way the removed tissue is microscopically examined, evaluating 100% of the surgical margins. The pathologic interpretation of the tissue margins is done on site by the Mohs surgeon, who is specially trained in the reading of these slides and is best able to correlate any microscopic findings with the surgical site on the patient. Advantages of Mohs surgery include:

Ensuring complete cancer removal during surgery, virtually eliminating the chance of the cancer growing back
Minimizing the amount of healthy tissue lost
Maximizing the functional and cosmetic outcome resulting from surgery
Repairing the site of the cancer the same day the cancer is removed, in most cases
Curing skin cancer when other methods have failed

Other skin cancer treatment methods blindly estimate the amount of tissue to treat, which can result in the unnecessary removal of healthy skin tissue and tumor re-growth if any cancer is missed.

Preparation and Recovery

While treatment of your skin cancer is your primary concern, reconstruction of the treated area is also important. After your Mohs surgeon is confident that all of the cancer has been removed, together you will determine how the wound will be repaired. In addition to removing skin cancer, fellowship trained Mohs College surgeons have specialized reconstructive surgery training for repairing the wound.

Options for Reconstruction:

Your surgeon can advise whether to have reconstruction immediately after surgery or at a later time. However, it is difficult to determine the extent of cancer beforehand.

After determining that the affected area is cancer free and reconstruction is necessary, the Mohs surgeon will review skin cancer reconstructive surgery options with you. Depending on the size of the tumor, depth of roots, and location, one of the following options will be selected:

Small, simple wounds may be allowed to heal by themselves (process known as secondary-intention healing)
Slightly larger wounds may be closed with stitches in a side-to-side fashion
Larger or more complicated wounds may require a skin graft. This can come from another part of the body. Alternatively, a flap of nearby skin might be used to cover the wound
On rare occasions, the patient may be referred to another reconstructive surgical specialist

Post-Operative Management
After Mohs surgery, your surgeon will schedule follow-up appointments. These appointments are to check your recovery and detect any cancer recurrence early. Since 2 out of 5 patients with one skin cancer will develop another within 5 years, follow-up is extremely important for early detection of any new lesions.