Evaluation of 7th Edition of AJCC Staging System for Nasopharyngeal Carcinoma

Purpose: To evaluate and improve the 7^th edition International Union against Cancer/American Joint Committee on Cancer staging system for nasopharyngeal carcinoma. Methods: A retrospective review of the data from 905 patients with biopsy-proven non-disseminated nasopharyngeal carcinoma was performed. All the patients were examined by magnetic resonance imaging (MRI) and received radiotherapy. Results: Satisfied distributions among the stages were observed in the 7^th edition staging systems. LRFS only differed in classifications betweenT1 and T3, T1 and T4 (P=0.022 and P=0.016, respectively). Significant differences were observed between patients without and with masticator space involvement for OS, DMFS and PFS (p<0.05). No statistically significant differences in LRFS were observed among different groups with anatomical masticator space involvement. The DMFS between N2 and N3b, N3a and N3b were lack of significance (P=0.060 and P=0.59). The T category and N category were independent prognostic factors for the major endpoints in the Cox multivariate regression analysis (P<0.01). Conclusion: This study confirmed the prognostic value of the 7^th edition UICC/AJCC staging system, the revisions of the 7^th edition staging system are acceptable. However, our study also revealed limitations in the current staging system and suggested some potential modifications in future revision.