Incidence of retropharyngeal lymph node involvement in oropharyngeal squamous cell carcinoma: a systematic review and meta-analysis.
BACKGROUND: Retropharyngeal lymph node (RPN) involvement in oropharyngeal squamous cell carcinoma (OPSCC) may influence prognosis, staging, radiotherapy target volumes, and treatment strategy. However, its true prevalence and association with clinicopathological factors remain incompletely defined. METHODS: A systematic review and meta-analysis was performed in accordance with the PRISMA 2020 statement. MEDLINE, EMBASE, EMCARE, PubMed, Web of Science, Scopus, and the Cochrane Library were searched from database inception to 15 June 2026. Studies reporting radiological or pathological assessment of retropharyngeal lymph node (RPN) involvement in oropharyngeal squamous cell carcinoma (OPSCC) were included. Pooled prevalence estimates were calculated using a random-effects model, with subgroup analyses according to tumour stage, nodal status, HPV status, and primary tumour subsite. RESULTS: Fourteen studies comprising 8,887 patients were included. The pooled prevalence of RPN involvement was (95% CI 11-16%; 95% PI 6-24%), with substantial heterogeneity. HPV-negative tumours demonstrated higher prevalence than HPV-positive tumours (21% vs 11%). Prevalence increased with advancing T stage, from 2% in T1 to 18% in T4 disease, and was higher in node-positive than node-negative disease (16% vs 1%). Tonsillar primaries showed higher prevalence than base of tongue tumours (14% vs 8%). Among patients with RPN involvement, the pooled distant metastasis rate was 16%. CONCLUSION: RPN metastases were identified in approximately one in eight patients with OPSCC and were more frequent in HPV-negative disease, advanced stage, and tonsillar primaries. These findings support careful evaluation of the retropharyngeal space during staging and may assist risk stratification in selected higher-risk patients.