Lymph node metastasis in head and neck squamous cell carcinoma: risk stratification, diagnosis, and management

Purpose To establish a risk-stratified management framework for cervical lymph node metastasis (LNM) in head and neck squamous cell carcinoma (HNSCC) by integrating AJCC 9th edition staging, the 2024 HNCIG extranodal extension (ENE) consensus, AI radiomics, and modern immunotherapy, with critical appraisal of clinical utility and external validation. Methods A PRISMA 2020-compliant systematic review of 49 high-quality studies identified through database search (January 2019–April 30, 2025), with 3 additional post-cutoff studies used for background context; stratified quality assessment was performed using RoB 2, NOS, AMSTAR 2, and QUADAS-2. Finding Unified pathological-radiological ENE criteria were consolidated for HNSCC; AI radiomics showed promising but insufficiently externally validated performance for occult metastasis prediction; risk-adapted algorithms integrating selective neck dissection, adjuvant anti–PD-1 immunotherapy, and de-escalation were constructed for specific risk strata. Conclusion This review provides a risk-stratified evidence synthesis for LNM management in HNSCC, while highlighting that radiomics models require prospective multicenter validation before clinical deployment, and that management recommendations should be applied within appropriate risk and disease strata.