Nasopharyngeal carcinoma with skull base invasion: a necessity of staging subdivision

To investigate prognostic values of nasopharyngeal carcinoma (NPC) with skull base invasion for optimal management, according to its extent of involvement.

From January 1985 through December 2000, 119 patients with histologically proven NPC were analyzed retrospectively with review of their computed tomography/magnetic resonance imaging and medical records. All patients underwent sequential chemoradiotherapy except 2 cases, which were treated concurrently. The mean duration of follow-up was 61 months (range 8-179). Potential prognostic factors were evaluated by univariate and multivariate analyses by the Kaplan-Meier method and the Cox model, with a particular emphasis on the extent of skull base invasion.

Skull base invasion was found in 46 (38.6%) of 119 patients. Cranial nerve palsy and intracranial extension was discovered in 34 (28.6%) and 23 (19.3%) of these patients, respectively. The sole erosion of the skull base was not found to be a poor prognostic factor. Patients with involvement of both anterior (I-VIII) and posterior (IX-XII) cranial nerves had a worse prognosis than those with involvement of either anterior or posterior cranial nerves (P = 0.0219). The presence of intracranial extension was the worst prognostic factor in NPC with skull base invasion (P = 0.0269). The advanced neck stage and histology did not affect the prognosis of NPC in the presence of skull base invasion.

Our results show that NPC with skull base invasion should be divided into the groups with, simple skull base erosion, minimal involvement of either anterior or posterior cranial nerves, multiple involvements of both cranial nerves, and intracranial extension.