From the Guidelines
For skin squamous cell carcinoma, a 4-6 mm margin is recommended for low-risk tumors, while high-risk tumors may require wider margins, with Mohs micrographic surgery often preferred for high-risk or cosmetically sensitive areas, as noted in the guidelines of care for the management of cutaneous squamous cell carcinoma 1.
Key Considerations
- The recommended surgical margins depend on the tumor's risk factors, including size, differentiation, and location, with low-risk tumors typically requiring smaller margins than high-risk tumors 1.
- For low-risk tumors, a 4-6 mm margin to a depth of the mid-subcutaneous adipose tissue with histologic margin assessment is recommended, as stated in the guidelines of care for the management of cutaneous squamous cell carcinoma 1.
- High-risk tumors may require wider margins, with some studies suggesting 6-10 mm or more, depending on the specific characteristics of the tumor, and Mohs micrographic surgery is often preferred for these cases, as it allows for complete margin assessment while preserving healthy tissue 1.
- The goal of surgical excision is to completely remove the tumor with clear margins to prevent recurrence while minimizing functional and cosmetic impact, with postoperative pathological confirmation of clear margins essential for all excisions 1.
Surgical Approaches
- Standard excision with a 4-6 mm margin is recommended for low-risk primary cSCC, with the depth of excision extending to the subcutaneous fat or deeper depending on tumor invasion, as noted in the guidelines of care for the management of cutaneous squamous cell carcinoma 1.
- Mohs micrographic surgery is recommended for high-risk cSCC, as it allows for complete margin assessment while preserving healthy tissue, and is often preferred for high-risk or cosmetically sensitive areas, as stated in the guidelines of care for the management of cutaneous squamous cell carcinoma 1.
- Curettage and electrodessication may be considered for low-risk, primary cSCC in non-terminal hair-bearing locations, but is not recommended for high-risk tumors, as noted in the guidelines of care for the management of cutaneous squamous cell carcinoma 1.
From the Research
Surgical Margins for Skin Squamous Cell Carcinoma
- The recommended lateral surgical excision margin (LEM) for low-risk squamous cell carcinomas (SCCs) is 4-6 mm, while Mohs surgery or resection with complete circumferential peripheral and deep margin assessment is recommended for high-risk SCCs 2.
- For SCCs greater than 20 mm in area with no other high-risk factors, 10-mm clinical margins may be used if the tumor can be repaired primarily 2.
- A study analyzing cutaneous SCC excisions found that the mean radial operative margin was 6.5 mm across all tumors and 8.4 mm for tumors greater than 2 cm, with an overall incomplete excision rate of 7.6% 3.
- Research suggests that narrower margins may be acceptable for high or very high-risk cSCC, with no significant differences in local relapse, SCC relapse, and SCC death between standard margin groups and narrower-margin groups 4.
- Re-excision of incompletely excised cutaneous SCC is influenced by histological findings, with positive re-excision predicting recurrence, and factors associated with residual tumor on re-excision similar to characteristics of high-risk SCCs 5.
- Global guidelines on surgical margins for nonmelanoma skin cancers, including SCC, vary, with more consistency in margin selection for low-risk basal cell carcinoma and low-risk cutaneous squamous cell carcinoma, but less consistency for dermatofibrosarcoma protuberans and Merkel cell carcinoma 6.