Mohs surgery
Mohs surgery, also known as Mohs micrographic surgery, is a specialized surgical technique designed to excise malignant skin tumors with precision. Developed in the 1930s by Dr. Fredric Mohs, this procedure gained prominence in the 1960s when it demonstrated a remarkable five-year cure rate of 100% for basal cell and squamous cell carcinomas. It is particularly beneficial for tumors located in cosmetically sensitive areas such as the face, neck, hands, and genitalia. The process involves removing the tumor along with a small margin of surrounding healthy skin, followed by immediate analysis of the excised tissue to ensure complete removal. This iterative approach continues until clear margins are achieved, minimizing unnecessary removal of healthy tissue and optimizing cosmetic results.
Typically performed under local anesthesia, Mohs surgery is well-tolerated and can take two to four hours. Following the procedure, patients receive detailed wound care instructions to aid recovery. While Mohs surgery boasts high cure rates—99% for basal cell carcinoma and 95-99% for squamous cell carcinoma—there are potential risks, including pain, infection, and scarring. Recent advancements have also established Mohs surgery as a feasible option for melanoma due to improved histological techniques. Overall, Mohs surgery remains a leading choice for treating certain skin cancers due to its effectiveness and careful approach to preserving surrounding healthy tissue.
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Mohs surgery
ALSO KNOWN AS: Mohs micrographic surgery
DEFINITION: Mohs surgery is a surgical technique for precisely excising malignant cutaneous tumors. It was developed in the 1930s by Dr. Fredric Mohs. In 1969, Dr. Mohs reported using the technique for excising basal and squamous cell carcinomas and claimed a five-year cure rate of 100 percent. Subsequent data and studies led to the validation of the technique within the surgical community. Mohs surgery is now commonly used for the resection of malignant and nonmalignant tumors in cosmetically sensitive areas such as the face and neck, hands, and genitalia.
Cancers treated:Basal cell carcinomas, squamous cell carcinomas
Why performed: With Mohs surgery, the tumor can be surgically excised with precision, maintaining the best surgical and cosmetic outcome. Accurate tumor margin assessment and high cure rates are achievable with this technique. In addition, Mohs surgery allows the patient to be spared the unnecessary removal of normal tissues, ultimately providing a more functional and cosmetically optimal outcome.
Patient preparation: The patient is screened for allergies to numbing medicines such as lidocaine. The surgical site is prepped in a sterile fashion. Local anesthesia is typically used, and the patient’s wound is covered between surgical stages.
Steps of the procedure: Mohs surgery is typically performed under local anesthesia by a dermatologist trained in the procedure in an outpatient setting. The procedure typically takes between two and four hours and is generally very well tolerated, with a low incidence of postsurgical complications.
During the procedure, the tumor and a small area of clinically normal-appearing skin around the tumor are excised. The tissue is then immediately processed by a histology technician, and the margins are evaluated by the surgeon. Mohs micrographic diagrams are used to map out the tissue for the histology technician and the surgeon. If the microscopic margins are positive, then their precise locations are noted on the Mohs map, and tissue is resected only from that area. This process is repeated in stages until the entire tumor is removed, and clear margins are seen.
Following the complete resection of the tumor, the defect is either closed immediately using various surgical repair techniques or allowed to close by secondary intention. The type of closure depends on the type of defect and the surgeon's preference.
After the procedure: The patient should be provided with thorough wound care instructions before discharge.
Risks: The risks of Mohs surgery include allergy to the numbing medication, scarring, pain, and infection.
Results: The procedure ideally results in the complete clearing of the tumor in question. The patient should be counseled that recurrence is always a possibility. In the mid-2020s, Mohs surgery remained the treatment of choice for basal and squamous cell carcinomas due to its accuracy and efficiency. It had a 99 percent cure rate in cases of basal cell carcinoma, and in cases of squamous cell carcinoma, it had between a 95 and 99 percent success rate. Although Mohs surgery was not previously used for melanoma skin cancers, advances in immunohistochemistry stains that can more precisely target melanoma cancers made it a viable option.
Bibliography
Hayes, Mileham. Practical Skin Cancer Surgery. Chatswood: Elsevier Australia, 2014.
“Mohs Surgery: For Skin Cancer, Procedure, Risks, Recovery.” Cleveland Clinic, 31 Aug. 2022, my.clevelandclinic.org/health/treatments/13312-mohs-surgery. Accessed 19 June 2024.
Morrissey, Matthew, Thomas Beachkofsky, and Steven Ritter. "When to Consider Mohs Surgery." Journal of Family Practice, vol. 62.10, 2013, 558–64.
Nouri, Keyvan. Mohs Micrographic Surgery. London: Springer, 2012.
Steinman, Howard K., and Kenneth G. Gross. Mohs Surgery and Histopathology: Beyond the Fundamentals. Cambridge: Cambridge UP, 2009.
Stranahan, Donald R., et al. “Advances in Immunostains Used in Mohs Surgery.” Journal of Drugs in Dermatology: JDD, vol. 9.7, 2010, pp. 760-3.
Vidimos, Allison T., Christopher C. Gasbarre, and Christine Lopez Poblete. Mohs Surgery. Philadelphia: Saunders, 2011.