Understanding Mohs Surgery

Mohs surgery is done to help treat skin cancer. During the surgery, a thin section of the tumor and a small area around it are removed. The removed tissue is looked at right away under a microscope. The process is then repeated. Sections of tissue continue to be removed and looked at under a microscope until no more cancer cells are found.

During standard tumor removal, the tumor and a margin of healthy tissue around it are removed all at once. Mohs surgery removes the tumor in portions that are examined. This makes it more likely that all the cancer is removed. There is a very low chance of it coming back. Also, less healthy tissue often needs to be removed than with standard tumor removal.

After the tumor has been removed, the surgeon can often fix the area during the same surgery.

Why Mohs surgery is done

Mohs surgery is most often used for skin cancer that is:

  • Large or fast-growing

  • Likely to spread

  • Likely to come back, or has come back

  • On an area where it is important to remove as little tissue as possible (such as the nose, lips, ears, eyelids, or hands)

  • Very aggressive

How Mohs surgery is done

The surgery is most often done in an office or surgery center. It is done on an outpatient basis. This means you go home after the surgery is done. The procedure can take up to 4 hours or longer. During the surgery:

  • You change into a patient gown or stay in your regular clothes.

  • The area around the tumor is injected with medicine. This numbs the area and prevents pain.

  • The surgeon removes the first layer of tissue. The area is covered with a small bandage.

  • You move to a waiting area.

  • The tissue is examined. This can take up to an hour or longer. During this time, you can read or watch TV.

  • You return to the surgical room to have more of the tumor removed.

This process is repeated until the removed tissue shows no more cancer cells. Once the tumor is removed, you and your surgeon can decide how best to repair the surgery site. The repair may be done right away. Or the repair surgery may be scheduled for another day.

Risks of Mohs surgery

  • Bleeding

  • Infection at the incision site

  • Nerve damage

  • Pain

  • Problems with reconstruction

  • Recurrence of the skin cancer and need for further treatment

  • Reopening of the incision after surgery

  • Scarring

  • Severe bruising