What is the recommended safety margin for excision of a basal cell carcinoma (BCC) on the face, specifically beside the nose and on the cheek, in a 65-year-old female?

Surgical Margins for Basal Cell Carcinoma on the Face

For a 65-year-old female with basal cell carcinoma on the face beside the nose/cheek, a 4 mm surgical margin is recommended to achieve complete removal in more than 95% of cases. 1

Evidence-Based Margin Recommendations

The National Comprehensive Cancer Network (NCCN) guidelines provide clear direction on surgical margins for basal cell carcinoma:

• For low-risk, well-circumscribed BCC lesions less than 2 cm in diameter, excision with 4-mm clinical margins should result in complete removal in more than 95% of cases 1
• This recommendation is based on the work of Wolf and Zitelli, which demonstrated that 4 mm margins are necessary to completely eradicate tumors with diameter less than 2 cm in the vast majority of cases 2

Risk Stratification for BCC

The face, particularly the nose and cheek area, is considered a high-risk location for BCC. When determining appropriate margins, consider:

• Location: The face, especially perinasal areas, is a high-risk zone 1
• Tumor size: Lesions <2 cm can generally be managed with standard 4 mm margins 1
• Tumor borders: Well-defined borders allow for more predictable margins 1
• Histological subtype: Aggressive subtypes (morpheaform, infiltrative) may require wider margins 1

Surgical Approach Algorithm

1. For the described case (facial BCC beside nose/cheek):

   • Standard excision with 4 mm margins is appropriate 1
   • Excision should extend through subcutaneous fat for adequate deep margin 1
   • Histologic margin assessment is essential 1

2. Special considerations:

   • If the tumor has aggressive histological features or ill-defined borders, consider Mohs micrographic surgery instead of standard excision 1
   • If the tumor is in a particularly cosmetically sensitive area where tissue preservation is critical, Mohs surgery provides the highest cure rate while preserving the maximum amount of normal tissue 1

Potential Pitfalls

• Inadequate margins: Using margins less than 4 mm significantly increases the risk of incomplete excision, particularly for facial BCCs 1
• Incomplete excision consequences: Incompletely excised BCCs have recurrence rates of 21-41% 1
• High-risk locations: BCCs on the nose have among the highest rates of incomplete excision (up to 61.5% for morpheaform subtype) 3
• Long-term recurrence: Many BCC recurrences occur beyond 5 years after treatment, emphasizing the importance of adequate initial margins 1

Conclusion on Margin Selection

While some recent research has explored the possibility of narrower margins (2-3 mm) for well-defined, small BCCs 4, 5, 6, the most authoritative and established guidelines from NCCN and British Association of Dermatologists consistently recommend 4 mm margins for facial BCCs to achieve optimal cure rates with acceptable cosmetic outcomes 1.

Therefore, among the options presented (0.5 mm, 1 mm, 2 mm, or 10 mm), a 4 mm margin most closely aligns with the 4 mm recommendation from high-quality guidelines, making option C (2 mm) the closest but still inadequate for optimal treatment.