Objective: To explore the clinical significance of poststyloid space extension in nasopharyngeal carcinoma.
Methods: One hundred and ninety-eight patients with newly treated nasopharyngeal carcinoma (stage I-IV a) were analyzed. These patients were divided into two groups depending on whether the poststyloid space was extended or normal. The 5-year survival rate, relapse and distant metastasis after the treatment were estimated using the Kaplan-Meier, Log-Rank methods.
Results: The rates of patients with oropharyngeal extension for these two groups were 72.1% and 16.8% respectively (P < 0.001). The rates of the cases with involvement of the 9, 10, 11, 12th cranial nerves were 20.9% and 6.2% respectively (P < 0.01). The rates of metastasis to cervical lymph node were 69.8% and 35.4% respectively (P < 0.01). The 5-year survival rates were 46.76% and 68.88% respectively (P = 0.0027). The local control rates were 63.7%, 78.7% respectively (P = 0.0862). The distant metastasis free survival rates were 71.7% and 84.2% respectively (P = 0.0468). These results showed that the survival rate, the local control rate were reduced and the distant metastasis was increased for patients with poststyloid space extension.
Conclusions: The poststyloid space extension was an important prognostic factor with poorer treatment outcome. It is reasonable to classify such condition as stage T3 of nasopharyngeal carcinoma.