Prognostic influence of parapharyngeal extension in nasopharyngeal carcinoma

Advanced parapharyngeal tumor involvement in nasopharyngeal carcinoma (NPC) had significant predictive value associated with poorer treatment outcome. Further subclassification of parapharyngeal invasion may be considered in the TNM staging system.

We conducted a retrospective study to elucidate the effect of parapharyngeal extension on treatment outcomes in patients with NPC who were treated with radiotherapy or concurrent chemoradiotherapy (CCRT).

A total of 99 patients with newly diagnosed NPC were enrolled in this study. The parapharyngeal space invasion examined by CT scan was identified and graded according to Sham and Choy's classification. Potentially significant parameters were analyzed by both univariate and multivariate methods using SPSS software.

The overall survival, recurrence-free survival, locoregional control survival and distant metastasis-free survival rates were affected by the presence of parapharyngeal space involvement (p<0.0001, p<0.0001, p<0.0001, p=0.002, respectively). In multivariate analysis accounting for all previously known prognostic factors, parapharyngeal invasion was associated with increased risk for any recurrence, locoregional recurrence, distant metastasis, and overall survival. After adjusting with TNM classification, parapharyngeal invasion was still an independent prognostic factor in NPC.