Prognostic value of lymph node ratio in laryngeal and hypopharyngeal squamous cell carcinoma: a systematic review and meta-analysis

BACKGROUND: Several recent studies have indicated that the lymph node ratio (LNR) is an independent prognostic factor for laryngeal and hypopharyngeal squamous cell carcinoma (LHSCC). The purpose of this paper is to assess the prognostic value of LNR and explore appropriate cutoff values by conducting a systematic review and meta-analysis. METHODS: Pubmed, Embase (via Ovid), and Cochrane library were systematically searched for studies on the prognostic value of LNR in LHSCC up to October 31, 2019. Then, Literature review, data extraction, and quality assessment of eligible studies were performed by two independent reviewers back-to-back. Lastly, Stata 14.0 software was hired to conduct a meta-analysis. RESULTS: A total of 445 articles were retrieved, and 13 studies published in English between 2013 and 2019 were included after the title/abstract and full-text screening. Among the 13 studies contributed to 4197 patients, seven studies were about hypopharyngeal squamous cell carcinoma (HPSCC), four studies about laryngeal squamous cell carcinoma (LSCC), and the remaining two studies about LHSCC. The meta-analysis results showed that shorter overall survival (OS) (HR 1.49; 95%CI: 1.18 to 1.88), disease-specific survival (DSS) (HR 1.66; 95%CI: 1.32 to 2.07) and disease-free survival (DFS) (HR 2.04; 95%CI: 1.54 to 2.71) were significantly correlated with a higher LNR in a random-effect model. The cutoff values of eligible studies were varied from 0.03 to 0.14, and the lowest significant LNR was 0.044. CONCLUSION: LNR is a valuable prognostic factor in the survival of LHSCC and may be used to improve the tumor staging systems, which, however, requires the solid support of more high-quality studies.