Sun & Skin News

Do You Know Mohs? What to Expect Before, During and After the Procedure

By Ali Venosa • September 21, 2021

Since doctors first began treating skin cancer, their techniques for removing tumors have evolved rapidly. There have been many valuable improvements over the years, but Mohs surgery has truly stood the test of time — it’s come to be accepted as the gold standard for removing the two most common forms of skin cancer, basal cell carcinoma and squamous cell carcinoma. It offers the highest cure rate while sparing as much healthy tissue as possible. Some surgeons are also successfully using Mohs surgery on certain cases of melanoma.

During Mohs surgery, a specially trained dermatologist removes a layer of visible cancerous tissue, then examines it under a microscope. If any cancer cells are seen, the surgeon removes another layer of skin from the exact spot on the skin where cancer cells remain. This process is repeated until no more cancer cells are found.

The Skin Cancer Foundation counts many talented Mohs surgeons as members. We asked three of them to explain what patients should expect before, during and after Mohs surgery.

The Preparation

Once you’re scheduled for Mohs surgery, it’s important to take note of any existing health conditions, according to C. William Hanke, MD, founder of the Laser and Skin Surgery Center of Indiana and a fellowship-trained Mohs surgeon in Indianapolis.

“For example, if a patient has a heart murmur or artificial joint, they should speak with their primary care physician to determine if preoperative antibiotics are necessary,” says Dr. Hanke, a senior vice president of The Skin Cancer Foundation.

If you have preexisting cardiovascular disease, it’s important to speak with your doctor as well — he or she may or may not instruct you to discontinue any blood thinners.

For those without any preexisting conditions, there are still a handful of things to keep in mind. Dr. Hanke recommends avoiding aspirin and other nonsteroidal anti-inflammatory drugs (including ibuprofen) for at least seven days prior to your surgery. Avoid alcohol and vitamin E a few days before as well. Dr. Hanke says a good night’s sleep and a normal breakfast are the way to go the day of the procedure. There is no need to fast, since local anesthesia is used for the surgery.

It’s best to clear your schedule the day of your Mohs procedure, as the process can take time. You may want to ask a loved one to accompany you to your appointment. Finally, if the surgery is on your face, make sure your skin is free of makeup.

The Procedure

Though undergoing surgery of any kind can be nerve-racking, a Mohs procedure shouldn’t involve a huge amount of pain or inconvenience.

“The procedure itself is usually much easier than patients anticipate,” says Ali Hendi, MD, a board-certified dermatologist fellowship-trained in Mohs surgery who practices in Chevy Chase, Maryland. “Most patients say, ‘Wow, that was it?’”

The local anesthesia injection is generally the most painful part of the experience. Once the area is numb, you may feel some pressure as the surgeon works, but removing the first specimen takes only a few minutes. Tissue processing usually takes an hour or two, though, so you may want to bring a book or magazine to pass the time, and make sure your phone is fully charged.


Dr. Hendi says that in his practice, about 40 to 50 percent of the time a Mohs procedure is finished in the first stage. If the tissue sample doesn’t come back clear of cancerous cells, the patient receives more anesthesia and the surgeon repeats the process. Once the site is clear of cancer cells, the wound may be left open to heal or the surgeon may close it, depending on its size and location.

Beyond the possibility of pain, many patients have cosmetic concerns about the surgery. They worry it will leave a noticeable scar.

“I tell my patients I have two goals for a Mohs procedure,” Dr. Hendi says. “First, cure them. Secondly, I want to make sure they keep their looks and heal up nicely.”

Though patients and their family members may always be able to tell they’ve had the surgery, typically it will be difficult for others to notice anything amiss after they’ve completely healed.

The Recovery

Your surgeon should provide explicit post-op directions, so you won’t need to guess at how to recover most effectively. Patients may even receive bags of supplies to help them with aftercare, according to C. Drew Claudel, MD, a fellowship-trained Mohs surgeon practicing in Goodlettsville, Tennessee. You’ll likely be instructed to avoid strenuous work or exercise for at least 24 to 48 hours, and told the possible warning signs of wound infection.

“I usually tell patients to expect a little discomfort — maybe including some bruising and swelling — but these symptoms usually resolve fairly quickly,” Dr. Claudel says. If you’re dealing with pain after the procedure, he suggests trying a cold compress, over-the-counter pain medication and lots of rest. Before you leave your doctor’s office, be sure to know whom to call if you have any concerns outside of office hours.

It’s important that you follow your doctor’s instructions for wound care, scar care and follow-up to achieve the best possible outcome.

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