Five things to know about Mohs surgery for skin cancer

Ian Maher, MD, wants to make things quick and easy for skin cancer patients.

Maher is a dermatologic surgeon with M Health Fairview and an associate professor at the University of Minnesota Medical School. He’s an expert in Mohs surgery, a surgical technique that treats skin cancer by gradually removing thin layers of skin from a skin cancer site until a patient is cancer free. Unlike other skin cancer surgeries, Mohs surgery can be completed in just a day with same-day testing to ensure all cancerous tissue is removed and give patients greater peace of mind. The procedure is essentially painless and is highly effective. It can be used to treat several forms of skin cancer, including basal cell carcinoma, squamous cell carcinoma, and melanoma.

In addition to performing Mohs surgery, Maher treats other complex skin tumors and is considered a national expert on post-skin cancer reconstruction. He writes and lectures extensively both at home and abroad on the latest methods in reconstruction. We caught up with Maher to discuss what you should know about Mohs surgery.

Mohs surgery is very precise.

During Mohs surgery, a dermatologic surgeon like Maher removes cancerous tissue one layer at a time. First, the surgeon outlines the incision they will make with ink to map the tumor. The patient is given a local anesthetic, and the doctor then removes the thinnest possible layer of cancerous tissue. While the patient waits, that layer is processed in an onsite pathology lab. After processing, the surgeon examines the removed tissue under a microscope to determine whether any cancer remains. If it does, the dermatologic surgeon can identify the precise location of the remaining cancerous cells.

At that point, the patient returns to the operating room so the surgeon can remove another layer of cancerous tissue. The process is repeated until the cancer has been completely removed. Roughly 80 percent of patients only need a single layer of skin removed to remove all the cancerous tissue. This layer-by-layer approach keeps the incision as small as possible to reduce scarring and promote healing.

In traditional skin cancer procedures, a pathologist may only study a small fraction of a much larger sample to determine whether any cancer remains, and the results often take days to process. Surgeons like Maher have been trained to act as both surgeon and pathologist. They remove the tissue, then conduct a comprehensive study of the entire sample to ensure a patient is cancer-free before moving on to reconstructive surgery.

“Because of the way we process these tissue samples, looking at 100% of the margin around the cancerous tissue, we can know for certain when we’ve removed all of the cancer,” said Maher, who has performed over 10,000 Mohs surgeries throughout the course of his career.

Mohs surgery minimizes scarring.

Mohs surgery only requires the smallest incision necessary to remove the cancer, which reduces scarring and minimizes the amount of reconstructive surgery needed. The process removes a minimal amount of normal skin surrounding the cancer—only taking what is needed to remove the cancer.

“Because we check the entire surgical margin, we are able to spare more normal skin, resulting in a smaller incision,” Maher said. “We always strive for the repair that leaves our patients with the best cosmetic and functional result. Our goal is to minimize scarring, so that within three months after the procedure, it’s not obvious that the patient has undergone surgery.”

Maher works with his patients to find a plan to return them to their normal appearance as quickly as possible. “Everybody is different, and I strive to get my patients the best cosmetic result possible with a plan that fits their life.” 

Maher has also developed and published a number of new reconstructive techniques, particularly for the nose and ear.

The procedure is quick and efficient.

Mohs surgeries can be completed in a day, in large part because dermatologic surgeons who perform these procedures act as both surgeon and pathologist. In traditional methods, surgeons and patients may be required to wait several days before learning from a pathologist whether any cancerous tissue remains around the surgical site.

“We’re able to process the tissue, look at it within an hour, evaluate it and then take more, if necessary,” Maher said. “We don’t move onto the repair until we know we’ve gotten the entire tumor. Most patients spend between two-and-a-half to four hours with us the day of the surgery.”

It has a high success rate.

Mohs surgery isn’t only precise and efficient, it’s also one of the most effective forms of treatment for certain types of skin cancer. For a standard skin tumor that’s being treated for the first time, the success rates are as high as 98 to 99%.

“This type of surgery offers one of the best cure rates for many types of skin cancer,” Maher said.

Mohs surgery is nearly painless.

Patients typically experience very little pain during and after Mohs surgery, apart from the initial injection of an anesthetic to numb the area beforehand. If patients are anxious about the procedure, our dermatologic surgeons can give them an oral medication in addition to the anesthetic to help them relax on the day of their surgery, Maher said.

“Typically, pain after the procedure is minimal and can be relieved by over-the-counter medications like Tylenol or Advil,” he added. “Less than five out of every 100 patients require prescription pain medications, and the vast majority of people have a pain level of zero out of 10 within two days.”

Learn more about our care for skin cancer, from diagnosis through treatment, or call 612-676-4834 to schedule an appointment.