Goal: The purpose of the current study was to investigate the long-term characteristics of radiation-induced cranial nerve injury in nasopharyngeal carcinoma (NPC) patients.
Patients and methods: We studied cranial nerve palsy (CNP) in 328 NPC patients who received radiotherapy between 1994 and 2006. Follow-up was 93.6% complete as of December 2009. A total of 72 patients with CNP were recruited for analysis (56 men and 16 women). Patients with evidence of residual or recurrent tumor accompanied by CNP were excluded. The characteristics of CNP and the relationship with the radiation fields as well as re-ratiotherapy were evaluated.
Results: After a mean follow-up of 11.2 years, 72 patients were found to have developed CNP. The latency of palsy ranged from 0.6–16.0 years. For the 67 patients with first course radiation, the glossopharyngeal and vagus nerves were the most vulnerable combination, occurring in 57 patients (85.1%). Patients with facial–cervical field radiation had a significantly longer latency comparing with that of patients with facial–cervical split fields (p = 0.021). In the first 5 years, 49.3% of patients developed CNP, while 40.3% presented CNP in the second 5-year period. In patients with first course radiation, 61 patients had more than one CNP. With regard to the 5 patients with re-radiation, most of them had multiple upper cranial nerve injuries.
Conclusion: Radiation therapy of NPC patients may lead to cranial neuropathy. Patients with facial–cervical radiation fields had a longer latency for the manifestation of CNP compared with those patients who were treated with split fields. In patients with re-radiotherapy, the frequency of upper cranial nerve injury increased greatly.