Performance of Staging Systems for Non-head and Neck Cutaneous Squamous Cell Carcinoma

Area of Science:

• Oncology
• Dermatology
• Cancer Staging

Background:

• Limited data exist on the efficacy of current staging systems for non-head and neck cutaneous squamous cell carcinomas (non-HNCSCCs).
• Accurate staging is crucial for predicting patient outcomes and guiding treatment decisions.

Purpose of the Study:

• To evaluate the performance of the Brigham and Women's Hospital (BWH) and American Joint Committee on Cancer 8th edition (AJCC8) staging systems.
• To assess the predictive accuracy of these systems for poor outcomes in non-HNCSCCs.

Main Methods:

• Retrospective analysis of 9300 non-HNCSCC cases from 11 institutions across two countries.
• Evaluation of local recurrence, metastasis, and disease-specific death as poor outcomes.
• Calculation of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and concordance index (c-index).

Main Results:

• Both BWH and AJCC8 systems demonstrated high specificity (0.98/0.96) and NPV (0.99/0.99) for predicting major poor outcomes.
• Sensitivities (0.48/0.49) and PPVs (0.17/0.13) were low for major poor outcomes.
• Concordance indices (c-indices) were moderately high (0.73/0.74), comparable to head and neck SCC literature.

Conclusions:

• The BWH and AJCC8 staging systems perform similarly for non-HNCSCCs, with acceptable performance for general use.
• The low sensitivity and PPV highlight the need for refinement of staging systems to improve prognostication accuracy.
• Further research is warranted to enhance the predictive capabilities of CSCC staging systems.