Evaluation of the American Joint Committee on Cancer Staging System for Cutaneous Squamous Cell Carcinoma and Proposal of a New Staging System

Purpose To identify and propose corrections for deficiencies in the American Joint Committee on Cancer (AJCC) system for staging cutaneous squamous cell carcinoma (CSCC). Materials and Methods Prognostic factors for CSCC were identified by retrospective analysis of the published literature. Limitations and deficiencies in the current AJCC staging system for CSCC were then determined using these prognostic factors. Results Size, histologic differentiation, location, previous treatment, depth of invasion, tumor thickness, histologic subtype, perineural spread, and scar etiology are the most powerful tumor prognostic indicators in patients with localized disease. The most important prognostic factors for patients with nodal metastases are the location, number, and size of the positive lymph nodes. Proposed changes for the T classification include increased stratification of tumor size, identification of patients with perineural invasion, and the addition of tumor thickness or depth of invasion. The N classification has been expanded to include the number and size of nodal metastases. Conclusion The current AJCC staging system for carcinoma of the skin has deficiencies that limit its use for CSCC. The proposed TMN staging system for CSCC more accurately reflects the prognosis and natural history of CSCC.