Introduction: Lymphoepithelial carcinoma (LC) is a rare malignancy that is a variant of undifferentiated carcinoma and accounts for 0.4% of malignant salivary gland tumors. It is associated with exposure to Epstein-Barr virus (EBV) in endemic areas. Current recommended treatment includes complete surgical excision and postoperative radiotherapy. Due to the limited case load and geographic skew of the neoplasm, population-based epidemiologic and clinical data are lacking.
Objective/ Hypothesis: This study is designed to analyze the demographic, clinicopathologic, and survival outcomes of patients with lymphoepithelial carcinoma of the head and neck cases from 1973-2014 using the Surveillance, Epidemiology, and End Results (SEER) database.
Subjects and Methods: This study is a population-based, concurrent retrospective database analysis of 1677 patients diagnosed with LC from 1973-2014. Frequency functions, Kaplan-Meier and Cox regression models were used to analyze demographics, treatment status and survival outcomes.
Results: A total of 1677 cases of LC were identified from the SEER database. The most common primary sites of LC are nasopharynx (49.6%), parotid gland (7.9%), and tonsil (6.6%). The average age at diagnosis is 51.11 and the range 50-59 contained a plurality of cases (23.4%). The male sex was predominant (69.4%) and the most common incident race was white (45.6%) with other (Asian/Pacific islander) second most common (37.3%). A significant predominance of cases were found in Alaska (1.3% vs. 0.1%, p<.001) and California (45.6% vs. 32.9%, p<.001) when compared to that of all other head & neck cancers in the SEER database. The most common grade at presentation is undifferentiated/anaplastic/grade IV (41.9%). The median overall survival is 8.5 years. 32.3% of diagnosed cases received surgical intervention. Overall 5-year survival was 55.6% and 5-year disease-specific survival (DSS) was 75.6%. Among patients with primary site surgery, DSS was improved (81.7% 95% CI: 79.9%-83.5% vs. 73% 95% CI: 71.6%-74%). On univariate analysis, male sex (p=0.04), married status (p=0.03), and primary site of nasopharynx (p<0.001) were associated with increased DSS. Black race was associated with a poor prognosis (p=0.004). These variables were included in COX multivariate analysis. Primary sites (p=<0.001), surgical status (p<0.001), and marital status (p=0.027) retained significance in disease specific survival.
Conclusions: Lymphoepithelial carcinoma of the head and neck is associated with a favorable prognosis. Unique to LC is an extraordinarily high Asian/Pacific islander prevalence, likely associated with ethnic and geographic predispositions. Sex, primary site, surgical therapy, marital status, and race are independent predictors of DSS. We present the first population-based analysis of LC, identifying the demographic, pathologic, and survival outcomes of the disease.