“Mohs” micrographic surgery was developed by physician and general surgeon Frederic E. Mohs while still a medical student at the University of Wisconsin-Madison in 1938. Mohs surgery is considered the most effective technique for the removal of skin cancer lesions, primarily basal cell carcinomas (BCCs) and squamous cell carcinomas (SCCs). The cure rate is over 98%.

The primary benefit of Mohs surgery is that it minimizes the removal of healthy tissue by progressively removing thin layers of cancerous BCCs or SCCs during a single doctor visit until the microscope indicates “clear margins.”

Mohs surgery overview

• During the first visit, the doctor examines and biopsies the suspected lesion(s).
• Generally, the doctor’s office calls the patient in 7-10 days with the lab results. If the lesion was found to be a BCC or SCC, Mohs surgery may be scheduled.
• The second visit is the actual Mohs surgery visit. It can last a few hours or as much as an entire day.
• Not every BCC or SCC is treated with the Mohs procedure. If the lesion is small and on the back, torso, or thigh – for instance – the doctor may do a simple excision (cutting out the tumor) since these parts of the body can afford a more aggressive cut. But, if the lesion is located on a part of the body where skin is more limited (nose, ear, etc.), the Mohs procedure is generally best so that the surgery site, repair and resulting scar are minimized.
• Some Mohs patients do not ask a family member or friend to accompany them on the surgery day – especially if the patient has Gorlin syndrome and has frequent surgeries. Many others do, however, for moral support or to provide transportation – especially if the bandaging hinders driving vision.

A Mohs patient should bring the following on a Mohs day:

• Food (snack, sack lunch, etc.) – The driver (and maybe the patient) may like to run grab a quick bite to eat during lab time since a Mohs day can be a long day.
• Drink (Some offices have a coffee maker.)
• Book or other reading material
• Laptop computer or other devices (Call ahead to see if the office has Wi-Fi.)
• Clothing layers (so not too cold or hot)

A Mohs patient should expect the following on a Mohs surgery day:

• Once the patient signs in and is called back to the surgery room, the Mohs surgeon typically marks the biopsy spot with a pen and then numbs the area using a local anesthetic injection. The patient is awake during all steps of the Mohs procedure.
• After the area is numb, the surgeon removes a conservative, thin layer of visible cancerous tissue with a scalpel. And then, a temporary bandage is applied.
• Not knowing if the visible specimen is “the tip of the iceberg,” the medical staff must examine the tissue under a microscope in the office lab. This analysis determines if the lesion has roots or extensions not visible from the surface.
• The patient relaxes in the lobby while the surgeon examines the first specimen under a microscope. The lab work and the wait time in the lobby typically takes roughly 60-90 minutes depending on the office and how many other Mohs patients are having surgery that day.
• Back in the operating room, if the microscope reveals more cancer cells, the surgeon injects more anesthesia, and the process is repeated until lab results indicate “clear margins” (no more cancer cells).
• Then, the surgeon determines whether to allow the wound to be left open to heal, or the surgeon may close the site with sutures. Dissolvable and/or removable stitches may be used depending on the location of the surgery. If the wound is more prone to opening (for instance, adjacent to the mouth or on the hand), stronger, removable sutures will be used. If removable sutures are used, the patient must return to the doctor’s office the following week to have the sutures removed by a nurse.
• In either case, the wound is protected with a pressure bandage which helps limit bleeding and swelling.
• After 24 hours, the pressure bandage may be removed at home, and the patient can gently shower, but should not allow the shower stream to be directed at the wound location.
• After showering, the patient should follow after care instructions he/she received from the nurse following surgery. Typically, wound care is simply cleansing, applying fresh Vaseline, and bandaging until the wound has healed.