Living in the Sunshine State has many advantages but also one disadvantage – you are more likely to be diagnosed with some form of skin cancer in your lifetime.
The most common skin cancers are basal cell and squamous cell carcinomas, according to Dr. Sean McGregor, board-certified dermatologist and Mohs surgeon with Cleveland Clinic Indian River Hospital. Fortunately, those types of carcinomas can be easily removed either by traditional excision or by the more precise Mohs surgery technique.
“The main difference between traditional excision and Mohs surgery is that Mohs surgery is done in real time with the tumor being examined in the in-house lab while the patient waits in the office, versus the traditional excision which requires cutting the tumor and sending it out to a lab for examination,” said Dr. McGregor.
“Mohs surgery is kind of like cutting a piece of pie in that we are removing the pie and the crust underneath the pie and examining it as we go. It gives us the ability to look at the complete margin, including the crust around and underneath the cancer, while at the same time conserve as much healthy tissue as possible.
“If the evaluation shows we didn’t get it all in the first pass, we can go back in and scrape another layer of the crust in the same office visit, whereas we’d have to wait a week or more to get the results back from a pathologist with the traditional excision.”
According to Mayo Clinic, the goal of Mohs surgery is to remove as much of the skin cancer as possible, while doing minimal damage to surrounding healthy tissue. It’s an improvement to standard local excision surgery which removes the visible cancer and a small margin of surrounding healthy tissue all at once. Mohs surgery allows surgeons to verify that all cancer cells have been removed at the time of surgery, which increases the chance of a cure and reduces the need for additional surgery.
Mohs surgery is the preferred method of treatment for the most common skin cancers such as basal cell carcinoma and squamous cell carcinoma. It’s especially useful for skin cancers that have a high risk of recurrence or that have reappeared after a previous treatment.
It’s also useful for cancers located in an area where you want to preserve as much healthy tissue as possible such as around the eyes, ears, nose, mouth, hands, feet and genitals. Those cancers that have undefined borders or are large or aggressive are also best treated with Mohs surgery.
Mohs surgery is done in stages, on an outpatient basis, in a procedure room near a laboratory that allows the surgeon to examine the tissue layer by layer after it’s removed. The surgeon uses a scalpel to remove the visible portion of the cancer along with a thin layer of tissue that is slightly larger than the visible tumor. The surgeon will then take the tissue to the laboratory for analysis where the tissue is cut into thin layered sections and examined under a microscope. The surgeon makes a map of where each piece of tissue was removed so that if a small area of cancer is found in one piece, he’ll know precisely where to continue the surgery.
If additional cancer is found, the surgeon will return and continue Mohs surgery by removing an additional layer of tissue from the affected area. Again, that tissue will be mapped and examined in the laboratory. The process is repeated, if needed, until the last tissue sample removed is cancer free.
This is a meticulous process that may take several hours, and the patient waits between each stage. Most of the time will be spent waiting for the results of the lab exams so you may want to bring a book or magazine to pass the time. You won’t be able to leave the surgeon’s office until the procedure is complete.
“The Mohs process can take upwards of 4-to-6 hours because it’s done in real time,” Dr. McGregor advised. “But the advantage is that once we know the margin is 100 percent clear, you know it’s all gone. While the traditional excision is quicker and you may only spend a half hour in the office, you have to wait a week or so for results and come back in and do it all over again if we didn’t get a clear margin in the first pass. We are able to get very high cure rates in different ways, so we discuss the options with the patient and decide which method would be best for them.”
The Mohs surgery cure rate is between 97 percent and 99 percent, compared to 92 percent to 95 percent for the traditional excision procedure.
Once the site is clear of all cancer cells, the wound may be left open to heal or the surgeon may close it with stitches. In some cases, the wound may need reconstruction with a skin flap or skin graft. Occasionally the surgeon may delegate the repair of the wound to another specialist such as a plastic surgeon, but the Mohs surgeon usually is a one-stop shop for skin cancer treatment and repair in the office surgical facility.
Dr. McGregor said the typical downtime after Mohs surgery in just one or two weeks. “We want the patient to take it easy and refrain from over-exertion or swimming while the wound is healing and, of course, to take precautions like wearing a hat and sunscreen when going out in the sun.”
While both Mohs and excision surgeries have high cure rates, it’s still advisable to have follow-up exams with your dermatologist at least once or twice a year. Data show that people who have been diagnosed with skin cancer have an increased risk of developing skin cancer again.
Dr. Sean McGregor completed a fellowship in Micrographic Surgery and Dermatologic Oncology in association with Mercer University School of Medicine in Macon, Georgia. Prior to the fellowship, he completed his dermatology residency at Wake Forest University School of Medicine in North Carolina and his medical training at the Philadelphia College of Osteopathic Medicine, Georgia Campus, in Suwanee, Ga. He is now accepting new patients at his Cleveland.