The prognostic significance of parapharyngeal tumour involvement in nasopharyngeal carcinoma.

From 1984 to 1989, 903 treatment-naive non-disseminated nasopharyngeal carcinomas (NPCs) were given primary radical radiotherapy. All patients had computed tomographic and endoscopic evaluation of the primary tumour. Potentially significant parameters were analysed by both univariate and multivariate methods for independent significance. In the whole group of patients, the male sex, skull base and cranial nerves(s) involvement, advanced Ho N-level, presence of fixed or partially fixed nodes and nodes contralateral to the side of the bulk of the nasopharyngeal primary, significantly determined survival and distant metastasis rates, whereas skull base and cranial nerve involvement, advanced age and male sex significantly worsened local control. However in the Ho T2No subgroup, parapharyngeal tumour involvement was the most significant prognosticator that determined distant metastasis and survival rates in the absence of the overriding prognosticators of skull base infiltration, cranial nerve(s) palsy, and cervical nodal metastasis. The local tumour control of the Ho T2No was adversely affected by the presence of oropharyngeal tumour extension. The administration of booster radiotherapy (20 Gy) after conventional radiotherapy (60-62.5 Gy) in tumours with parapharyngeal involvement has led to an improvement in local control, short of statistical significance.