Squamous Cell Carcinoma of the Skin (SSC)

SCC is a non-melanoma skin cancer:
- That arises from keratinocytes of the epidermis
- It accounts for one fifth of all skin cancers:
  - Is more lethal than basal cell carcinoma:
    - As difficult-to-treat metastatic disease:
      - Can occur in up to 5% of patients
Management of SCC, like basal cell carcinoma:
- Consists of adequate local control:
  - Several characteristics have been identified to stratify lesions at high risk for recurrence:
    - These include:
      - Tumor size greater than 2 cm
      - Ulcerated
      - Location on the:
        
        Lips / nose / forehead / chin and neck (H areas of the face)
      - Ill-defined borders
      - Previous radiation
      - Chronic scar
      - Immunosuppression
      - Recurrent tumors
      - Poor differentiation
      - Deep Clark level invasion
- Presence of risk factors directs local therapy:
  - As lesions with no risk factors can be safely excised with 4 mm to 6 mm margins
- With one or more risk factors:
  - Larger margins should be obtained, and 1-cm margins are recommended, if possible (given local tissue constraints)
- The use of SLN biopsy for high-risk SCC has been reported in several small, single institutional reports:
  - However, its impact on patient outcomes has not been well defined
A highly successful alternative to standard surgical excision is Mohs micrographic surgery, performed by experienced dermatopathologists:
- This involves serial resections of the tumor with real-time mapping and complete peripheral and deep pathologic evaluation to direct immediate further resection:
  - It has the lowest recurrence rates when compared to curettage / electrodessication, standard surgical excision, and radio therapy
Surgical excision with grossly negative margins, with immediate primary closure is inappropriate:
- As the tumor’s size alone is a negative risk factor precluding smaller (4- to 6-mm) margins
References:
- Brodland DG, Zitelli JA. Surgical margins for excision of primary cutaneous squamous cell carcinoma. J Am Acad Dermatol. 1992; 27:241-248.
- National Comprehensive Cancer Network. NCCN Clinical Practice Guidelines in Oncology. Basal cell and squamous cell cancers. Available at: http://www.nccn.org.
- Renzi C, Caggiati A, Mannooranparampil TJ, et al. Sentinel lymph node biopsy for high risk cutaneous squamous cell carcinoma: case series and review of the literature. Eur J Surg Oncol. 2007;33:364-369.
- Rowe DE, Carroll RJ, Day CL Jr. Prognostic factors for local recurrence, metastasis, and survival rates in squamous cell carcinoma of the skin, ear, and lips: implications for treatment modality selection.J Am Acad Dermatol.1992;26:976-990.