Lymphoepithelial carcinoma of the oral cavity and pharynx: a SEER population-based cohort study

Lymphoepithelial carcinoma (LEC) of the oral cavity and pharynx is a rare cancer, with poorly understood clinicopathological characteristics and prognosis. Only a few case reports or small case series have been reported, so the characteristics and survival of patients with this disease remains unclear. The present study aimed to describe the clinicopathological characteristics and determine the factors associated with survival of this uncommon cancer.

A population-based study was carried out to investigate clinical characteristics and prognosis of LEC of the oral cavity and pharynx using the data from Surveillance, Epidemiology and End Results (SEER) database. Log-Rank test and Cox regression analysis were performed to determine the prognostic factors, and a prognostic nomogram was further constructed. The propensity-matched analysis was conducted to compare the survival of nasopharyngeal LEC and non-nasopharyngeal LEC patients.

Totally, 1025 patients were identified, including 769 nasopharyngeal LEC patients and 256 non-nasopharyngeal LEC patients. The median OS of all patients was 232.0 months (95% CI 169.0-258.0). The 1-, 5-, 10- and 20-year survival rates were 92.9%, 72.9%, 59.3%, and 46.8%, respectively. Surgery significantly prolonedg the survival of LEC patients (P<0.01, mOS: 190 m vs. 255 m). Radiotherapy, as well as radiotherapy after surgery, prolonged the mOS (P<0.01 for both). The survival analysis demonstrated that old age (>60 years), lymph node (N3) and distant metastases were independent factors for poor survival, whereas radiotherapy and surgery were independent factors for favorable survival. The prognostic nomogram was established base on these five independent prognostic factors (C-index = 0.70; 95% CI 0.66-0.74). In addition, no significant difference in survival time between nasopharyngeal LEC and non-nasopharyngeal LEC patients were observed.

LEC of the oral cavity and pharynx is a rare disease, and old age, lymph node and distant metastases, surgery and radiotherapy were significantly associated with prognosis. The prognostic nomogram could be used to make individual predictions of OS.