Lymph Node Status and Outcomes for Nasopharyngeal Carcinoma According to Histological Subtypes: A SEER Population-Based Retrospective Analysis.

Abstract

We aimed to investigate the clinical effect of histological subtypes on survival in nasopharyngeal carcinoma (NPC), and assess the effect of nodal stage on outcome according to histological subtypes. Patients with non-metastatic NPC were identified from the Surveillance, Epidemiology and End-Results (SEER) database between 2004 and 2014. Statistical analysis was performed using the chi-squared test, Kaplan-Meier methods, and multivariate Cox regression models. We identified 2845 patients in this study including 1218 (42.8%), 849 (29.8%), and 778 (27.3%) patients with keratinizing squamous cell carcinoma (KSCC), differentiated non-keratinizing squamous cell carcinoma (DNKSCC), and undifferentiated non-keratinizing squamous cell carcinoma (UNKSCC), respectively. The multivariate analysis indicated that patients with UNKSCC subtype had better NPC-specific survival (NPC-SS) (P < 0.001) compared to KSCC (P < 0.001) and DNKSCC (P < 0.001) patients. The 5-year NPC-SS was 75.2%, 77.9%, and 88.9% in patients with KSCC, DNKSCC, UNKSCC, respectively (P < 0.001). Subgroup analysis showed that advanced nodal stage was related to lower NPC-SS in patients with DNKSCC and UNKSCC but not in patients with KSCC. Histology is an independent prognostic factor in patients with NPC. However, advanced nodal stage is not associated with lower survival in KSCC.