From the Guidelines
Mohs micrographic surgery is the recommended treatment for high-risk skin cancers, particularly basal cell carcinomas and squamous cell carcinomas located in cosmetically sensitive areas like the face, or for tumors that are large, aggressive, recurrent, or have ill-defined borders. This technique offers the highest cure rates (up to 99% for previously untreated cancers) while preserving the maximum amount of healthy tissue 1. The procedure involves surgically removing the visible tumor and a small margin of surrounding tissue, which is immediately examined under a microscope while the patient waits. If cancer cells are still present at the edges of the removed tissue, additional layers are excised from precisely where the cancer remains until all margins are clear of cancer cells.
Key Benefits of Mohs Micrographic Surgery
- High cure rates for high-risk skin cancers
- Preservation of maximum amount of healthy tissue
- Can be performed under local anesthesia as an outpatient procedure
- Recovery time varies based on the extent of surgery, but most patients can resume normal activities within a few days to weeks
- Post-operative care includes keeping the wound clean, applying prescribed ointments, and protecting the area from sun exposure to prevent recurrence
Indications for Mohs Micrographic Surgery
- High-risk basal cell carcinomas and squamous cell carcinomas
- Tumors located in cosmetically sensitive areas like the face
- Large, aggressive, recurrent, or ill-defined tumors
- Tumors with high-risk features, such as perineural involvement or sarcomatoid/spindle cell growth patterns
Limitations of Mohs Micrographic Surgery
- May not be suitable for tumors with aggressive histopathologic growth patterns poorly visualized with frozen sections
- Tissue blocks from Mohs layers are not available for molecular testing or further evaluation of high-risk or unusual features by using paraffin sections
- Requires careful selection of tumors appropriate for treatment with Mohs micrographic surgery and evaluation by frozen sections to minimize limitations 1.
From the Research
Mohs Technique for High-Risk Skin Cancers
The Mohs technique, also known as Mohs micrographic surgery (MMS), is a highly effective treatment for high-risk skin cancers, including cutaneous squamous cell carcinoma (SCC) and basal cell carcinoma.
- Effectiveness of MMS: Studies have shown that MMS is effective in treating high-risk SCC, with low recurrence rates and disease-specific mortality 2, 3.
- Advantages of MMS: MMS is a pathology-controlled surgery with high intrinsic value due to its low risk of recurrences, making it a recommended treatment for high-risk non-melanoma skin cancers 3.
- Indications for MMS: MMS is particularly useful for treating skin cancers in critical sites, recurrent tumors, and tumors with aggressive histologic features 3, 4.
- Treatment Outcomes: A study of 215 patients with high-risk SCC treated with MMS reported a local recurrence rate of 1.2% and a metastasis rate of 2.3% 2.
- Comparison with Traditional Surgery: MMS has been shown to be superior to traditional surgery in treating high-risk non-melanoma skin cancers, with a lower risk of recurrences and better cosmetic outcomes 3.
- Emerging Therapies: Recent studies have also explored the use of immunotherapies, such as PD-1 inhibitors and oncolytic viruses, in the treatment of high-risk cSCC, which may be used in conjunction with MMS 5.