Prognostic Value of Cranial Nerve Invasion in T4‐Stage Nasopharyngeal Carcinoma: A Retrospective Cohort Study With a Median Follow‐Up of 136 Months

Background The objective of this study was to evaluate the prognostic value of cranial nerve invasion (CNI) in T4‐stage nasopharyngeal carcinoma (NPC) patients with nonmetastatic. Methods We retrospectively analyzed 299 T4‐stage NPC patients with nonmetastatic disease in the Cancer Hospital of Shantou University Medical College. The primary outcome was the overall survival (OS), and the secondary outcome was locoregional relapse‐free survival (LRRFS). Results CNI was observed in 159 (53.2%) NPC patients with T4‐stage disease. The mean follow‐up period was 136 months (range, 3–168 months). Multivariate analyses confirmed that age, pericavernous extension, lower cervical lymph nodes metastasis, CN II and CN X invasion were significant for OS. Multivariate analyses confirmed that prevertebral muscle invasion (PMI) was significant for LRRFS, whereas CNI was not significant for LRRFS. In T4‐stage NPC patients, significant differences were observed between the none and CNI groups in terms of the 5‐ and 10‐year OS rates (70.7%, 61.9% vs. 61.0%, 51.4%; p = 0.03), respectively. No significant difference was observed between the none and CNI groups in terms of the 5‐ and 10‐year LRRFS rates (87.4%, 78.1% vs. 88.1%, 79.8%; p = 0.71), respectively. In terms of OS, there were significant differences between the none and CN II, CN IX, CN X invasion, multiple CNI, unilateral CNI, and PMI groups, respectively (all p < 0.05). Significant differences were observed between the none and CN VII invasion and PMI groups in terms of LRRFS (both p < 0.05). Conclusions CNI significantly affected T4‐stage NPC patients' survival, although it had no discernible impact on local recurrence. This study elucidates the prognostic significance of CNI among patients with T4‑stage NPC, thereby enabling clinicians to precisely evaluate prognosis and implement optimal therapeutic interventions.