Comparison of TNM-based stage grouping versus UICC/AJCC stage grouping (7th edition) in malignant parotid gland tumors

Background: Although the UICC/AJCC's TNM staging of the 7th edition was improved in 2002, there are still shortcomings concerning the prognostic quality. Alternative TNM-based stage-groupings such as the T and N Integer Score (TANIS) where shown to have a better prognostic quality for various kinds of head and neck tumors in the past. The aim of the study was to compare the prognostic value of the 7th edition of the UICC/AJCC TNM-classification for carcinoma of the parotid gland with different TNM-based stage groupings.

Methods: The retrospective analysis included 180 patients with carcinoma of the parotid gland diagnosed between 1986 and 2007. The stage grouping system of the 7th edition of the UICC/AJCC and TNM-based stage-groupings (TANIS-3, TANIS-8, Snyderman, Berg and Hart) were tested for their prognostic significance. Overall survival (OS) was plotted by Kaplan-Meier analysis. Prognostic factors were identified through univariate and multivariate analysis.

Results: In univariate analysis all stage-groupings had a highly significant impact on overall survival (p<0.05), however in multivariate analysis, only the TANIS-8 scheme (p=0.008) and Snyderman scheme (p=0.047) predicted OS, while the UICC/AJCC-classification did not predict OS significantly (p=0.381).

Conclusion: In comparison to other TNM-based stage groupings the UICC/AJCC-classification did not provide significant prediction of OS, while alternative stage-groupings such as the TANIS-8 had a higher prognostic value.