Prevalence and prognostic impact of synchronous distant metastases in patients with hypopharynx squamous cell carcinomas: a SEER-based study

Background: The prognosis of hypopharynx squamous cell carcinoma (SCC) patients with distant metastasis is poor. We sought to explore prevalence and prognostic impact of synchronous distant metastases among patients with hypopharynx SCC in this study. Methods: Patients with histologically proven hypopharynx SCC were extracted from the Surveillance, Epidemiology and End Results (SEER) database between 2010 and 2014. We examined the relationship between tumor factors and distant metastases using Chi-squared tests and we evaluated the association between survival and different variables using the methods of Kaplan-Meier. Univariate analysis was performed using the log-rank test. Multivariate analyses with the Cox proportional hazards model were used to test the independent significance of the predictors, and two-tailed p-values less than 0.05 were considered statistically significant. Results: We finally identified 1780 patients who were diagnosed with hypopharynx SCC and the most frequent site of distant metastases was lung. Some clinical characteristics, including age, gender, race, histological grade, T classification and N classification were independent risk factors. Higher T or N category, posterior wall of hypopharynx cancers and multiple sites of metastases were associated with poorer overall survival. For cancer-specific survival, elderly patients with higher T category, advanced N category, posterior wall of hypopharynx cancers, multiple sites of metastases and no surgery therapies to the primary tumor were associated with worse survival. Conclusion: This is the first SEER analysis assessing prevalence and prognostic impact of synchronous distant metastases in a large cohort of patients with hypopharynx SCC. Poorer prognosis was associated with elderly patients, higher T category, advanced N category, posterior wall of hypopharynx cancers, no surgery therapies to the primary tumor and more metastatic sites