Number of positive lymph nodes and lymph node ratio predict recurrence and survival in hypopharyngeal cancer based on SEER database and validation of real-world data.

PURPOSE: This study investigated the impacts of the number of positive lymph nodes (NPLN) and lymph node ratio (LN ratio) for patients with hypopharyngeal squamous cell carcinoma (HPSCC) based on SEER database, which were validated in the real-world data of China. METHODS: A total of 520 patients from SEER database were analyzed. Then 195 patients with pathologically stage III or IV HPSCC in our center were retrospectively studied. RESULTS: In the SEER database, NPLN >/= 3 was found in 36.9% of patients. Multivariate analysis revealed that LN ratio >/= 0.138 was significant with poorer overall survival (OS) (hazard ratio [HR] = 1.525, p = 0.001) and cancer-specific survival (CSS) (HR = 1.697, p < 0.001), so was the NPLN >/= 3 (HR = 1.388, p = 0.013; HR = 1.479, p = 0.008). Patients with NPLN >/= 3 were found in 103 (52.8%) in our center. Multivariate analysis confirmed a significant association regarding OS (p = 0.005) or CSS (p = 0.003) between patients with LN ratio >/= 0.138 or not. In addition, disease recurrence rate differed significantly between the patients with NPLN >/= 3 (27.2%) and NPLN < 3 (14.1%, p = 0.026). Moreover, postoperative chemoradiotherapy (CCRT) was significantly associated with better prognosis in patients with NPLN >/= 3. CONCLUSION: In the SEER database, NPLN >/= 3 and LN ratio >/= 0.138 were independent poor prognostic factors for patients with HPSCC. Whereas identifying worldwide cut-off values for LN ratio is difficult and surgeon-dependent. In our cohort, adjuvant CCRT was beneficial for OS in patients with NPLN >/= 3.