What is the recommended treatment for a patient with moderate to well-differentiated squamous cell carcinoma (SCC) on the forehead?

Treatment for Moderate to Well-Differentiated Squamous Cell Carcinoma on the Forehead

For a moderate to well-differentiated SCC on the forehead, surgical excision with 4-6 mm margins extending to mid-subcutaneous fat with histologic margin assessment is the recommended treatment, with Mohs micrographic surgery being the preferred option if the tumor has high-risk features. 1

Risk Stratification

The forehead location requires careful consideration as it is a cosmetically sensitive area, though not classified as the highest-risk anatomic site (which includes ear, lip, nose, eyelids, and scalp). 1 Key factors to assess include:

• Tumor size: Lesions >2 cm are considered high-risk 1
• Histologic grade: Moderate to well-differentiated tumors (Broders' grade 1-2) are generally lower risk than poorly differentiated lesions 1
• Depth of invasion: Extension into subcutaneous tissue increases risk 1
• Recurrence status: Primary versus recurrent disease 1

Primary Treatment Approach

For Low-Risk Tumors (<2 cm, well-defined borders):

• Standard surgical excision with 4-6 mm margins to the depth of mid-subcutaneous adipose tissue with histologic margin assessment 1, 2
• This approach achieves 95% complete removal rates for clinically well-defined, low-risk tumors 1
• Histologic confirmation of clear margins is essential, as incomplete excision is associated with worse prognosis 1

For High-Risk Features (>2 cm, ill-defined borders, or recurrent):

• Mohs micrographic surgery is recommended as it provides the highest cure rates and allows complete histologic margin control while preserving maximum normal tissue 1, 3
• If Mohs surgery is unavailable, standard excision with margins of 6 mm or greater should be performed with comprehensive peripheral margin examination 1
• The forehead's cosmetically sensitive nature makes tissue preservation particularly important, favoring Mohs surgery when available 1

Critical Technical Considerations

Depth of excision is paramount: Recent evidence demonstrates that 94% of incomplete excisions involve the deep margin, not the radial margin. 4 Therefore:

• Excision must extend to mid-subcutaneous fat at minimum 1
• Deep margin assessment is more critical than achieving wider radial margins 4
• Place orienting sutures to allow accurate pathologic assessment of margin location 1

Avoid delayed reconstruction until histologic confirmation of complete excision is obtained, particularly for high-risk tumors. 1 This prevents the need for re-excision through reconstructed tissue.

Alternative Treatment Modalities (When Surgery Not Feasible)

If surgical therapy is contraindicated or refused after discussion of risks and benefits:

• Radiation therapy (superficial radiation, brachytherapy, or external electron beam) can be considered for low-risk tumors, though cure rates may be lower than surgery 1, 3
• Curettage and electrodesiccation may be considered only for low-risk, primary SCC in non-terminal hair-bearing locations 1
• Cryosurgery may be considered for low-risk lesions when more effective therapies are contraindicated, but requires experienced hands 1
• Topical therapies (imiquimod, 5-FU) and photodynamic therapy are NOT recommended based on available data 1

Pathologic Assessment Requirements

The surgical specimen should be evaluated for:

• Tumor grade and differentiation 1
• Depth of invasion (subcutaneous extension) 1
• Perineural invasion 1
• Margin status with distance measurements 1, 5
• Presence of aggressive histologic subtypes 1

A histologic margin of at least 5 mm is associated with improved survival in advanced cases, emphasizing the importance of adequate excision depth and width. 5

Follow-Up Protocol

• Annual screening for new keratinocyte cancers and melanoma is required after diagnosis 1
• 95% of recurrences occur within 5 years, necessitating vigilant follow-up during this period 2, 3
• Clinical examination with imaging (CT or MRI) if recurrence is suspected 1, 2
• Patient education on self-examination 3

Common Pitfalls to Avoid

• Inadequate depth of excision: This is the most common cause of incomplete excision, not insufficient radial margins 4
• Proceeding with immediate complex reconstruction before confirming clear margins on high-risk tumors 1
• Using curettage or cryotherapy for tumors on the forehead without careful risk assessment, as these lack histologic margin control 1
• Underestimating tumor extent based solely on clinical appearance, particularly with ill-defined borders 1