Abstract 1091P
Background
The AJCC8 shows heterogeneity for high-risk cutaneous squamous cell carcinoma (CSCC). The Brigham and Women’s Hospital (BWH) and the Tübingen’s stratification systems offer different proposals to AJCC8 and our group identified prognostic subgroups within T3-AJCC8, where most high-risk CSCCs are classified. The objective of this study was to compare the distinctiveness, homogeneity, monotonicity, prognostic accuracy and concordance of these alternative staging systems for the subset of high-risk CSCC staged as T3-AJCC8.
Methods
Retrospective cohort study of 196 cases of high-risk CSCC. All tumors were classified according the three alterative staging systems. Pair-wise comparison was performed through McNeemar test, and distinctiveness, homogeneity and monotonicity of the staging systems were also assesed. The prognostic accuracy was compared by means for Akaike AIC and BIC indexes and the concordance among staging systems was later compared by means of Harrell’s C-index and Gonen and Heller’s concordance probability estimation (CPE).
Results
The AJCC8-T3b/T3c represented 51.5% of the total cases, the BWH-T2b/T3 47.4% and the Tübingen system (3-4 points) 34.2%. BWH’s and Salamanca’s showed some overlap between each other and differ from Tübingen’s. The prognostic accuracy revealed that Tübingen’s is more efficient for local recurrence, and Salamanca’s and BWH’s are better for major events and for disease-specific death. Concordance analysis is better with any of the alternative systems than with the official AJCC8.
Conclusions
Alternative staging systems may partially overcome the heterogeneity and low prognostic accuracy of AJCC8 and stratify high risk CSCC more precisely. The combination of risk factors should be considered in future staging systems for CSCC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Javier Cañueto.
Funding
Javier Cañueto is partially supported by the grants PI18/000587 (Instituto de Salud Carlos III, Cofinanciado con Fondos FEDER).
Disclosure
All authors have declared no conflicts of interest.