Management of Cutaneous Squamous Cell Carcinoma on the Neck

Introduction to Treatment Modalities

• The American Academy of Dermatology recommends Mohs micrographic surgery (MMS) for high-risk cutaneous squamous cell carcinoma (cSCC) on the neck, while standard excision with 4-6 mm margins is appropriate for low-risk tumors 1, 2

Risk Stratification

• High-risk features of cSCC include tumor size ≥2 cm in diameter, depth of invasion ≥4 mm or Clark level V, poor differentiation, perineural invasion, lymphovascular invasion, invasion of fascia, muscle, or bone, recurrent tumor, and immunosuppressed patient, with location on high-risk anatomic sites also considered 1, 3

Treatment Algorithm

• For low-risk primary cSCC on the neck, standard excision with 4-6 mm clinical margins to mid-subcutaneous fat with histologic margin assessment is recommended, achieving approximately 5.4% local recurrence rates and 8.1% five-year recurrence rates 1, 2
• For high-risk cSCC on the neck, MMS is the recommended treatment modality, with evidence showing 3.1% five-year recurrence rates for primary cSCC compared to 8.1% for standard excision 2, 3

Outcomes of Treatment Modalities

• MMS achieves better recurrence rates than standard excision for tumors ≥2 cm (25.2% vs 41.7%), poorly-differentiated cSCC (32.6% vs 53.6%), and recurrent cSCC (10% vs 23.3%) 3

Pathology Requirements

• The pathology report must document degree of cellular differentiation, depth of invasion, perineural invasion, lymphovascular invasion, invasion of deeper structures, margin status, and number of high-risk features present 1

Biopsy and Treatment

• If the initial biopsy is inadequate for risk stratification, repeat biopsy before definitive treatment, as recommended by the American Academy of Dermatology 2