Abstract
PURPOSE: To compare the clinical characteristics and survival outcomes of patients with ascending type (type A), descending type (type D), and mixed type (type AD) of nasopharyngeal carcinoma (NPC) in non-endemic areas. MATERIALS AND METHODS: The cohort included 628 patients diagnosed with type A, type D, and type AD of NPC between January 2009 and December 2014. Type A was defined as T(3-4 ) N(0-1) , type D as T(0-1 ) N(2-3) , and type AD as T(3-4 ) N(2-3) . Propensity score matching (PSM) was performed to balance clinical factors and match patients. Kaplan-Meier methods and Cox proportional hazards models were used to evaluate the impact of different NPC types on survival outcomes. RESULTS: There were 145 patients with type A, 194 with type D, and 289 with type AD. However, after PSM, there were only 130 patients with each type. Compared with patients with type A, those with type D had lower 5-year disease-specific survival (96.9% vs 91.5%) and distant metastasis-free survival (92.3% vs 77.7%) and higher local relapse-free survival (88.5% vs 96.9%) (p < 0.05 for all). Patients with type AD may have an increased risk of disease progression (progression-free survival, 56.9% vs 74.6% and 66.2%) and death (overall survival [OS], 76.9% vs 85.4% and 85.4%) (p < 0.05 for all) compared to patients with the other two types of tumors. We further analyzed the metastasis trend. Similar metastasis patterns were observed in types AD and D, and types AD and A had similar recurrence trends. The mortality rate of patients with types AD and D in the first 3 years after metastasis was remarkably higher than that of patients with type A. CONCLUSIONS: In non-endemic areas of China, metastases and recurrence patterns differed across tumor types. Type AD has the worst OS, and the clinical process is more radical. Type D has a lower recurrence rate, higher metastasis, and disease-related mortality rates, and poorer prognosis after metastasis than type A.