A clinical verification on evaluation standard of the Chinese 2008 staging system of nasopharyngeal carcinoma for oropharynx involvement

Abstract

Objective To clinically verify the rationality of evaluation standard of oropharynx involvement in the Chinese 2008 staging system for nasopharyngeal carcinoma (NPC).Methods 333 consecutive patients with newly diagnosed,untreated,and nonmetastatic NPC were included.All patients had an MRI examnation of the nasopharynx and neck.The status of oropharynx involvement were evaluated.Results Of the 333 patients with NPC,26 (7.8 ％) patients presented with oropharynx involvement.Tumor invasion into oropharynx was highly related to tumor invasion into nasal cavity,parapharyngeal space,skull base,medial pterygoid muscle,paranasal sinuses,intracalvarium and masticator space excluding medial pterygoid muscle (P ＜ 0.050).The oropharynx involvement was associated with poorer 5-year overall survival (OS) and distant failure-free survival (DFFS) (38.1％ vs 72.6 ％,P＜ 0.001 and 49.1％ vs 84.5 ％,P＜ 0.001,respectively).By multivariate analyze,it was observed that oropharynx involvement was a significant predictive factor for OS and DFFS (P ＜ 0.001,P ＜ 0.001).Significant differences were observed in the 5-year OS (38.1％ vs 80.9 ％,P ＜ 0.001) and DFFS rates (49.1％ vs 89.3 ％,P ＜ 0.001) between the patients with oropharynx involvement and stage T2 patients.Conclusions MRI-evidenced oropharynx involvement had a negative impact on OS and DFFS in NPC patients.The oropharynx involvement is associated with poorer 5-year OS and DFFS compared with stage T2.The evaluation standard of oropharynx involvement for NPC in the Chinese 2008 staging system could be revised. Key words: Chinese 2008 staging of nasopharyngeal carcinoma; Nasopharyngeal neoplasms; Oropharynx; Prognosis; Magnetic resonance imaging