From the Guidelines
Recommended excision margins for high-risk skin cancers, such as basal cell carcinomas (BCC) and squamous cell carcinomas (SCC), are 4-6 mm for BCC and 6-10 mm for SCC, depending on the specific risk factors and location of the tumor. The choice of excision margin is based on several factors, including the type and size of the tumor, its location, and the patient's overall health. For high-risk BCCs, a margin of 4-6 mm is typically recommended, while high-risk SCCs generally require a margin of 6-10 mm 1. Factors that classify these cancers as high-risk include location (such as on the face, ears, lips, or scalp), large size (typically >2 cm), aggressive histological subtypes, recurrent lesions, poorly defined borders, and immunosuppression in the patient. Complete excision with histologically clear margins is crucial for preventing recurrence. Mohs micrographic surgery is often preferred for high-risk lesions in cosmetically sensitive areas as it allows for tissue conservation while ensuring complete tumor removal through immediate microscopic examination of margins 1. Some key points to consider when determining the appropriate excision margin include:
- The size and location of the tumor
- The type of skin cancer (BCC or SCC)
- The patient's overall health and medical history
- The potential for recurrence and metastasis
- The need for adjuvant radiation therapy or other treatments. In general, the goal of excision is to remove the tumor completely while preserving as much healthy tissue as possible. This can be achieved through standard excision, Mohs micrographic surgery, or other surgical techniques, depending on the specific needs of the patient 1. Post-excision, patients should receive regular follow-up examinations as they have an increased risk of developing subsequent skin cancers. It is also important to note that the excision margin may need to be adjusted based on the specific characteristics of the tumor and the patient's individual needs 1. Overall, the key to successful treatment of high-risk skin cancers is complete excision with histologically clear margins, which can be achieved through a combination of careful planning, precise surgical technique, and regular follow-up care.
From the Research
Excision Margins for High-Risk Skin Cancers
- The recommended lateral surgical excision margin (LEM) for high-risk basal cell carcinomas (BCCs) is Mohs surgery or resection with complete circumferential peripheral and deep margin assessment 2.
- For high-risk squamous cell carcinomas (SCCs), the recommended LEM is also Mohs surgery or resection with complete circumferential peripheral and deep margin assessment 2.
- If the BCC or SCC is >20 mm in area with no other high-risk factors and can be repaired primarily, 10-mm clinical margins may be used 2.
Factors Influencing Excision Margins
- Tumor size, subtype, and location are important factors in determining the appropriate excision margins 2, 3.
- High-risk factors for recurrence and metastasis include prior tumors, ill-defined borders, aggressive histologic patterns, and perineural invasion 4.
- The choice of excision margin may also depend on the patient's overall health, the location of the tumor, and the potential for reconstruction 5.
Variations in Guideline Recommendations
- There is a lack of international consensus on recommendations for surgical excision margins for nonmelanoma skin cancers, including BCC and SCC 3.
- Guideline recommendations are more consistent for low-risk BCC and SCC, but less consistent for high-risk tumors and other types of skin cancer 3.
- The American Society for Radiation Oncology has developed guidelines for the use of radiation therapy in the treatment of BCC and SCC, including recommendations for excision margins 5.