Clinical and Radiological Outcomes After Curative-Intent Induction Chemotherapy for Primary Advanced Oral Cavity...

Background/Objectives: The role of induction chemotherapy (IC) in advanced oral cavity squamous cell carcinoma (OCSCC) remains controversial. This study evaluated patient-level changes in primary-tumour and cervical nodal dimensions, subsequent definitive treatment, and survival after curative-intent IC. Methods: We retrospectively analysed 38 patients with primary, non-metastatic OCSCC treated with curative-intent IC between 2009 and 2024. Recurrent disease, second primary tumours, non-squamous histology, non-oral primary sites, baseline metastatic disease, direct chemoradiotherapy, and palliative systemic treatment were excluded. A prespecified simplified unidimensional radiological analysis was performed. The maximum axial primary-tumour diameter, the largest baseline cervical node, and total recorded nodal burden were compared before and after IC. Baseline nodes absent after IC were coded as 0 mm only when disappearance was confirmed on post-IC anatomical imaging. The overall survival (OS) was measured from IC initiation. Results: Primary-tumour measurements were evaluable in 25 patients. Median diameter decreased from 55.0 to 46.0 mm, corresponding to a median change of -13.5% (p = 0.049). The largest baseline node was evaluable in 19 patients and decreased from 17.0 to 13.0 mm, a median change of -16.7% (p = 0.004). Total nodal burden changed by a median of -8.3% (p = 0.257). Primary-tumour change did not differ significantly from largest-node change (p = 0.073) or total nodal-burden change (p = 0.860). TP and TPF showed no difference in primary-tumour change (p = 0.954). During a median follow-up of 40.4 months, 16 patients died. Median OS was 45.1 months and 5-year OS was 35.6%. Conclusions: IC produced heterogeneous, generally modest radiological changes. The largest baseline node decreased significantly, whereas total nodal burden did not. These data do not establish the superiority of one regimen or a causal survival benefit from surgery and should be considered hypothesis-generating.