When is Mohs surgery indicated for basal cell and squamous cell carcinoma?

Mohs micrographic surgery is especially effective in treating basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) of the face and other cosmetically sensitive areas, because it can eliminate the cancer while sparing surrounding normal skin. It is also ideal for the removal of recurrent skin cancers. In these tumors, cancer cells persist in areas of scar tissue, and the clinical margins of the recurrent tumor are often indistinct. Cure rates are 99% for primary basal cell cancers and 95% for recurrent tumors. Other indications for Mohs’ surgery include

• BCC with aggressive histopathologic features, such as morpheaform or sclerotic (desmoplastic), micronodular, superficial spreading, and infiltrative growth patterns, subtypes which often extend beyond visualized margins
• Excessively large or deeply invasive cancers
• Primary BCC or SCC with poorly defined borders, especially those present in locations known to have high recurrence rates (nasolabial fold, nasal ala, medial canthus, pinna, and postauricular sulcus)
• Any BCC or SCC adjacent to or within an orifice, such as nostrils or ear canals
• Any location where maximum preservation of normal tissue is paramount (e.g., nasal tip, nasal ala, lips, eyelids, ears, genitalia, fingers)
• Tumors with positive margins after standard excision
• Tumors in immunosuppressed patients

Otley CC, Salasche SJ: Mohs’ surgery: efficient and effective, Br J Ophthalmol 88:985–988, 2004.