Prognostic Influence of Parapharyngeal Space Involvement in Nasopharyngeal Carcinoma Based on MRI
LI Juan, MO Hao-yuan, MAI Hai-qiang, et al. (State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China)
[Purpose] To investigate the prognostic influence of parapharyngeal space involvement in nasopharyngeal carcinoma based on magnetic resonance imaging (MRI). [Methods] One hundred and eighty-five cases with nasopharyngeal carcinoma M0 stage, tumor extension to parapharyngeal space was staged according to the degree of the parapharyngeal space extension: patients without parapharyngeal involvement recorded as grade 0, with parapharyngeal involvement but without area of carotid sheath invasion recorded as grade 1, with area of carotid sheath invasion recorded as grade 2. The survival was calculated by Kaplan-Meier method, prognostic factor was analyzed by Cox multivariate model. [Results] Parapharyngeal space involvement was significantly associated with marrow invasion (r=0.15, P=0.041). Multivariate analysis showed parapharyngeal involvement was not an independent prognostic factor, but the area of carotid sheath invasion was an independent prognostic factor which affected overall survival and distant metastasis. [Conclusion] Parapharyngeal involvement alone does not affect the prognosis, and the area of carotid sheath invasion is an independent prognostic factor.