Mohs surgery is a specialized procedure used to treat basal cell carcinoma, the most common type of skin cancer. It involves removing cancerous tissue layer by layer while examining each layer under a microscope to identify remaining cancer cells. This technique allows surgeons to assess the surgical margins during the procedure and preserve as much healthy tissue as possible.
Basal cell carcinoma develops in the basal cells of the skin, which produce new skin cells as older ones are shed. It is commonly associated with ultraviolet radiation from sunlight or tanning devices. Although this cancer rarely spreads to distant organs, it can grow into surrounding tissues and cause damage if left untreated. Mohs surgery is a tissue-sparing treatment that allows doctors to remove cancerous cells while carefully examining the surrounding margins. The procedure combines surgical removal with microscopic examination, helping determine whether additional tissue needs to be removed during the same appointment.
Mohs micrographic surgery is performed by a specially trained surgeon who removes the visible skin cancer along with a thin layer of surrounding tissue. The removed tissue is processed and examined under a microscope to check for cancer cells at the edges and base of the specimen. If cancer remains, the surgeon removes another layer from the specific area where the cells are identified.
This process continues until the examined margins show no remaining cancer cells. Because the tissue is mapped and evaluated during surgery, the technique helps remove the cancer while minimizing unnecessary removal of healthy skin.
Doctors may consider Mohs surgery for basal cell carcinoma when the cancer has characteristics that make complete removal particularly important.
High risk of recurrence: Mohs surgery may be recommended for cancers that have returned after previous treatment.
Sensitive locations: Tumors on the nose, eyelids, lips, ears, and other cosmetically or functionally important areas may benefit from tissue preservation.
Ill-defined borders: Some basal cell carcinomas do not have clearly visible edges, making their full extent difficult to determine.
Aggressive growth patterns: Certain microscopic types of basal cell carcinoma may extend beyond their visible boundaries.
Tissue preservation: Examining the surgical margins helps the surgeon remove cancerous tissue while limiting the removal of unaffected skin.
The suitability of Mohs surgery depends on the tumor's size, location, microscopic characteristics, previous treatments, and the patient's overall circumstances. Other treatments may be appropriate for selected low-risk basal cell carcinomas.
Mohs surgery is generally performed under local anesthesia, allowing the patient to remain awake while the treatment area is numbed. The duration varies depending on the tumor, the number of tissue layers requiring removal, and the complexity of wound repair.
The procedure usually follows several stages. First, the surgeon identifies and marks the treatment area. The visible cancer and a thin layer of surrounding tissue are then removed. The tissue is prepared for microscopic examination, and the surgeon evaluates the margins. If cancer cells remain, another layer is removed from the affected area. Once the margins are clear, the wound is assessed to determine whether it can heal naturally or requires stitches or reconstructive repair.
Recovery depends on the wound's size and location, as well as the method used to close it. Patients receive instructions for wound cleaning, dressing changes, and follow-up appointments.
Wound care: Keep the surgical site clean and follow the surgeon's instructions for dressings and prescribed ointments.
Activity restrictions: Avoid strenuous exercise or activities that may stretch the wound until the healthcare provider advises that they are safe.
Expected healing: Mild swelling, bruising, tenderness, or limited bleeding may occur during the initial recovery period.
Possible complications: Infection, scarring, bleeding, changes in skin sensation, and delayed wound healing are possible risks.
Follow-up examinations: Regular skin checks are important because people who develop basal cell carcinoma may develop additional skin cancers.
Patients should contact their healthcare provider if they experience increasing pain, spreading redness, pus, fever, or bleeding that does not stop with the recommended measures. Healing time varies, and scars may continue to change in appearance over several months.
Mohs surgery offers precise margin assessment and can preserve healthy tissue, but it does not eliminate every risk of recurrence or future skin cancer. Patients should discuss the expected results, alternatives, wound repair options, and follow-up schedule with their dermatologist or surgeon to understand how treatment applies to their individual condition.