Assessment and treatment strategies for occult contralateral lymph node metastasis in hypopharyngeal squamous cell carcinoma patients with ipsilateral node-positive necks.

Hypopharyngeal squamous cell carcinoma (HSCC) is an aggressive disease with poor prognosis, yet studies have largely been more qualitatively focused. Our study aims to quantitatively predict the risk of occult contralateral lymph node metastasis (cLNM) for HSCC patients with ipsilateral lymph node metastasis (iLNM). This will be based on pre- and post-operative indexes to guide the selection of prophylactic contralateral lymph node dissection (cLND) and postoperative adjuvant treatments. Multivariate analyses of 462 primary HSCC patients with iLNM showed that the age of patients, subregions of tumor, pathological T (pT) stage, ipsiateral MLS and metastatic lymph node number (MLN), and lymph nodal necrosis were independent cLNM risk factors. These were used to construct two nomograms that can effectively predict the contralateral neck involvement in HSCC patients with ipsilateral positive lymph nodes. The first nomogram (pre-model) provides quantitative assessment on the necessity of cLND, while the second nomogram (post-model) informs regions of interest for therapeutic radiation. Overall, patients deemed high-risk of cLNM by pre-model should receive cLND. Post-operation, patients deemed high-risk of cLNM by post-model should receive therapeutic radiation targeting contralateral neck lymph nodes, moderate-risk group warrants comparatively lower dose contralaterally, while low-risk group requires only follow-up.