Organ‐Preserving Complete Response to Sequential Induction Chemoimmunotherapy and Concurrent Chemoradiotherapy in Locally Advanced Squamous Cell Carcinoma of the Floor of the Mouth: A Case Report

A 52-year-old male with T4aN0M0 floor of the mouth squamous cell carcinoma who refused surgery received sequential organ-preserving therapy: induction chemoimmunotherapy (3 cycles of tislelizumab 200 mg d1, docetaxel 75 mg/m² d1, cisplatin 75 mg/m² d1-3) followed by concurrent chemoradiotherapy (cisplatin 100 mg/m² q21d + radiotherapy 69.96 Gy/33f). Complete clinical response was achieved. At 36-month follow-up, the patient remained disease-free with preserved speech and swallowing. Significant quality-of-life improvement was confirmed by EORTC QLQ-C30/H&N35. This regimen demonstrates durable organ-preserving efficacy for surgery-declined locally advanced HNSCC.