Mohs Micrographic Surgery is the most advanced and effective treatment available today for skin cancer. The procedure is performed by specially trained surgeons who have completed at least one additional year of fellowship training (in addition to the physician’s three-year dermatology residency) in a certified Mohs fellowship by the American College of Mohs Surgery. The physician serves as surgeon, pathologist, and reconstructive surgeon for complete integration of care. Mohs surgery is the most exact and precise method of tumor removal. It minimizes the chance of regrowth and lessens the potential for scarring or disfigurement.
Initially developed by Dr. Frederic E. Mohs in 1941, the Mohs procedure is a state-of the-art treatment that has been continuously refined over 70 years. Certain types of cancers in specific locations have a tendency to grow with microscopic “roots” that make tumor removal difficult with standard techniques. The Mohs surgeon is able to see beyond the visible disease using a microscope to precisely identify and remove the entire tumor layer by layer, while leaving the surrounding healthy tissue intact and unharmed. This microscopic examination occurs immediately in the Mohs lab while you wait.
Advantages of Mohs Micrographic Surgery for Selected Skin Cancers:
- Has the highest cure rate (up to 98–99%)
- Spares the most normal surrounding skin during cancer removal
- Minimizes scarring and the chance for disfigurement
- Is the most exact and precise method of tumor removal
- Efficient: allows everything to be completed in one day with certainty
- Safe & Cost Effective: outpatient surgery, using local anesthesia only
Why does my cancer need Mohs Surgery?
Mohs Micrographic Surgery is effective for most types of skin cancer and is most commonly used to treat basal cell carcinoma and squamous cell carcinoma. Standard surgical excision is still the treatment of choice for malignant melanoma, which we perform at SeaCoast Skin Surgery. Your referring doctor has special expertise in deciding which tumors need Mohs Micrographic Surgery. There are many factors that contribute to the decision-making process. Mohs surgery is usually the treatment of choice when the tumor is located on the central face, eyelids, nose, lips, ears, mouth, or cheek. These are known as the high-risk areas of the body for skin cancer. Tissue sparing is also especially important in these areas:
- A skin cancer has recurred after being treated in the past.
- The tumor is very large.
- The cancer is very aggressive in its growth or microscopic appearance.
- The borders of the tumor are not clearly defined.
- The cancer is located in a highly sensitive cosmetic area.
- Scar tissue exists in the area of the cancer.
- The patient has an immune deficiency such as a solid organ transplant.
Skin cancers are removed to prevent the tumor from further invading and destroying the normal structures that surround it and from spreading to other parts of the body (this is called metastasis). Metastasis is very rare except in melanoma and a few other unusual forms of skin cancer that are not common.
The Process: How does Mohs surgery work?
The procedure begins with local anesthesia to the surgical site. After this has taken effect, the visible portion of the tumor or biopsy site is gently scraped with a curette. This helps to delineate the area involved by the tumor. Tumor cells don’t stick together well like bricks with bad mortar. The tumor will “shell out” when scraped with the curette. Next, the Mohs surgeon removes a small and thin “pancake-like” layer of tissue around the surgical site. During this process, a precise Mohs surgical map is made of the tissue and removal site.
The tissue is then transported to the laboratory where it is marked, prepared, and sectioned into slides for the Mohs surgeon to analyze under the microscope. The surgeon then examines all of the surgical margins to check for evidence of remaining cancer cells. The entire bottom and outer edge of the Mohs section (“pancake”) are checked for cancer. This ensures that any small roots or fingerlike projections of cancer do not elude detection and cause a tumor to recur. It is this special processing and examination of all the tissue margins that makes Mohs surgery different and more effective than standard techniques for indicated tumors.
If any of the sections contain cancer cells, the surgeon marks the exact location of the tumor on the Mohs map and then returns to the patient for another layer. This time the surgeon only has to remove tissue in those specific areas marked on the map. The rest of the surgical site is left alone, sparing normal skin and minimizing the cosmetic impact. This process is repeated in stages until the cancer is completely removed.
Reconstruction – Repairing the Wound
The Mohs surgeon is also extensively trained in reconstructive procedures and often will perform the necessary reconstruction to repair the wound. As soon as the affected area is declared cancer-free, the Mohs surgeon discusses post-surgical options with the patient, such as:
- A small, simple wound may be allowed to heal on its own.
- A slightly larger wound may be closed with stitches.
- Larger wounds may require a skin graft or a flap.
- If the tumor is very large, another surgeon with special skills may be called upon to assist with reconstruction.
About our Mohs Surgery
Dr. Viehman received his training for Mohs surgery at Duke University Medical Center from 1997–1998 under the direction of Dr. Robert E. Clark, MD, PhD. This was a specially certified Mohs Micrographic Surgery fellowship approved and accredited by the American College of Mohs Surgery. Dr. Viehman then practiced in Cary North Carolina at the Cary Skin Center for 10 years, performing thousands of Mohs surgery cases. Our laboratory is directed by Dr. Viehman, CLIA certified, and has specially trained laboratory personnel.
Selected patients with a diagnosis of squamous cell carcinoma in situ may be candidates for laser therapy. Laser therapy has been very effective for treating this tumor in specially selected cases. The laser allows a very precise treatment with little to no visible scarring. The surgical margins are not examined microscopically with the laser.
Patients with a diagnosis of melanoma or other tumors may receive a standard surgical excision if indicated.