We asked top experts to answer the most common questions about Mohs surgery.
- What exactly is it?
Mohs surgery is named after Frederic Mohs, a professor of surgery at the University of Wisconsin, who developed the treatment in the 1930s. “It’s a very tissue-sparing technique, where we go layer by layer, examining 100 percent of the margin in order to trace out the cancer using a microscope,” says Engelman.
You’ll be awake for the procedure, which is done under local anesthesia. The surgeon starts by cutting out a small piece of the tumor with a scalpel. A lab technician then freezes and stains the tissues for the surgeon to look at under a microscope.
“Cancer grows like roots of a tree,” explains Brett Coldiron, MD, the founder of The Skin Cancer Center in Cincinnati and an assistant clinical professor at the University of Cincinnati. “What we do [during Mohs surgery] is cut out a disc of skin and check for roots poking through. It’s very obvious under the microscope.”
“Mohs surgery can tout cure rates of 99 percent.”
Dendy Engelman, MD, dermatologist and Mohs surgeon
If a root is visible, the surgeon will go back and remove another layer of the tumor, repeating the same process until the entire cancer is gone. “Very rarely do we go past three passes,” says Coldiron.
- Who should get it?
“Moh’s surgery is very useful around the eyes, nose, mouth, and ears,” says Coldiron. “It’s also useful around the cheek if it’s a larger tumor.” Additionally, Mohs surgery can be performed on the hands, feet, and neck — areas where you’d want to preserve as much tissue as possible, says Engelman.
While Mohs surgery is generally used on basal and squamous cell cancers, in some cases it can be used to treat melanoma, especially if the cancer is thin or confined to the outer layer of skin. “Patients should ask their Mohs surgeon if this a procedure they offer, as not all Mohs specialists treat melanoma with Mohs,” says Engelman. Visit the American College of Mohs Surgery web site to find out if your dermatologist is a Mohs specialist.
- How long does it take?
Expect to be at the doctor’s office for approximately one to three hours. After your surgeon removes the first layer of tissue, which takes about 10 minutes, you’ll be sent to the waiting room for about a half hour while the surgeon examines the tumor.
Then, you’ll be brought back to the exam room to either get stitched up, which takes another 20 minutes, or have another piece of the tumor removed.
- Will it hurt?
No more than a biopsy, says Engelman. The area is numbed with enough lidocaine, a local anesthetic that reduces pain, to last for about two and a half to three hours. “The discomfort is minimal — there’s just that initial stick [of the needle],” says Engelman. “You may feel a little bit of pressure [during the procedure], but you don’t feel pain.”
Afterwards, most patients only experience minimal pain. “Certain areas like the scalp, legs, or areas under tension (like skin over joints) may be more sensitive and may require prescription strength pain medication for one to three days post-surgery, but the vast majority of surgeries do not require prescription analgesics,” says Engelman.
If you do experience pain, take extra-strength Tylenol — but avoid aspirin, ibuprofen, or naproxen in the first few days after surgery because they can increase your risk of bleeding.
- Will there be a scar?
Yes — but it’ll become less noticeable over time. “It may take six months for the redness to fade and for the scar to settle down, but six months down the road, most patients are happy with the final result,” says Coldiron.
To ensure the wound heals nicely, follow the post-operative care instructions given to you by your doctor, says Engelman. “Moist wounds have been found in studies to heal faster than those left exposed to air,” she says. “The scar formed tends to have a better aesthetic appearance when kept moist and covered with a bandage.”