The strength/weakness of the AJCC/UICC staging system (7th edition) for nasopharyngeal cancer and suggestions for future improvement

Summary Background and purpose To evaluate the current AJCC/UICC staging system (7th edition) for nasopharyngeal carcinoma and to explore for future improvement. Materials and methods A total of 985 patients, initially staged with preceding 5–6th edition, were retrospectively re-staged with the 7th edition. All were assessed by magnetic resonance imaging, and all 945 non-disseminated patients were irradiated with conformal/intensity-modulated technique. Results Staging factors by both the 5–6th edition and the 7th edition were strongly significance for important endpoints ( p < 0.001). Down-staging of the previous T2a to T1 and, stages IIA to I in the 7th edition was appropriate. However, the impacts on overall stage distribution and prognostication were minimal. Further down-staging of the current T2 to T1, N2 to N1, stages II to I, and merging of N3a and N3b, stages IVA and IVB were suggested. With the 7th edition, the 5-year disease-specific survival (DSS) was 100% for stage I, 95% for II, 90% for III, 67% for IVA, 68% for IVB and 18% for IVC. The corresponding DSS for the proposed stages I, II, III and IV were 95%, 86%, 67% and 18%, respectively. Conclusions The changes introduced in the 7th edition were appropriate, but the magnitude of improvement was minimal. With improving results by modern management, further simplification of the staging system is suggested. The proposed system could lead to more accurate prognostication, further validation is warranted.