Mohs surgery is a specialised technique for removing skin cancers. Mohs surgery differs from other skin cancer treatment in that if allows the immediate and complete microscopic examination of the removed cancer tissue so that all the extensions of the cancer can be removed. Mohs surgery has the highest reported cure rate of all treatments of skin cancer although if is important to emphasise that no cancer surgery has a 100% success rate.
Treating all skin cancers with Mohs surgery is not necessary. It is most commonly used for patients with tumours on the face close to important structures such as the eyelids, nose, mouth and ears. It is also used for patients where reconstructive surgery is most likely to be performed.
How is Mohs surgery done?
The steps of Mohs surgery are:
- Your skin cancers will be removed in an operating theatre in the Dermatology Department. The skin round the cancer is made completely numb using an injection of local anaesthetic. You will not be asleep (ie. you will not have a general anaesthetic).
- The visible cancer is removed with a thin layer of additional tissue. A detailed diagram (Mohs map) of the removed specimen is drawn. The wound is dressed and you-will return to the waiting room.
- The specimen is colour-coded. The tissue is frozen and prepared info very thin slices for examination under the microscope. This is the most time-consuming part of the procedure, often requiring an hour or more to complete.
- The surgeon examines the entire surgical margin of the removed tissue under the microscope. All microscopic roots of the cancer can be identified and pinpointed on the Mohs map. You will have to wait in the waiting room while this occurs.
- If more cancer is found, you will return to the operating theatre and the surgeon uses the Mohs map to remove additional tissue only where the cancer is present.
- The process is repeated until all the cancer is removed.
How long does if take?
Most cases can be completed in three or fewer stages, requiring less than-four hours. However no one can predict how extensive a cancer will be because the size of a skin cancer’s roots cannot be determined in advance. We therefore ask that you reserve the entire day for surgery.
What happens after the Mohs surgery is completed?
When the cancer is removed, the surgeons will discuss with you the options. These may include:
- Allowing the wound to heal naturally, without additional surgery (this often produces the best cosmetic effect). In this case the wound will be dressed regularly by hospital staff or your own practice nurse until it is completely healed.
- Wound closure using stitches by the dermatological surgeons.
- Referral to another specialist surgeon, generally a plastic surgeon for wound closure.
Will it leave a scar?
Yes, any form of surgery will leave a scar. Mohs surgery will leave one of the smallest possible wounds, and therefore, a smaller final scar.