Submental Island Flap Versus Free Flap Reconstruction in Oral Squamous Cell Carcinoma After Neoadjuvant Immunochemotherapy: A Propensity Score Matched Analysis

ABSTRACT Background The optimal reconstructive approach following neoadjuvant immunochemotherapy (NICT) and surgery for locally advanced oral squamous cell carcinoma (OSCC) remains debated. This study compared pedicled submental island flap (SIF) and free flap (FF) reconstruction in this contemporary treatment setting. Methods We conducted a retrospective comparative study of 212 consecutive patients with locally advanced OSCC treated with NICT followed by surgery. Propensity score matching (1:1) yielded a balanced cohort of 54 SIF and 54 FF patients. Outcomes included disease‐free survival (DFS), overall survival (OS), operative time, complications, recovery milestones, and patient‐reported quality of life (QoL) assessed via EORTC QLQ‐C30/H&N35 at baseline, 3, 6, and 12 months. Results Operative time and hospital stay were significantly shorter for SIF (4.5 ± 1.1 vs. 6.3 ± 1.4 h, p < 0.001; 8.1 ± 2.5 vs. 11.8 ± 3.1 days, p < 0.001). Flap survival and major complication rates were comparable ( p > 0.05). Median follow‐up was 38.5 months. No significant differences were observed in DFS (HR = 0.90, 95% CI: 0.41–1.98, p = 0.796) or OS (HR = 0.83, 95% CI: 0.34–2.00, p = 0.678). However, QoL recovery was superior in the SIF group, with significantly greater improvements in Global QoL (81.5 ± 8.2 vs. 73.9 ± 10.1, p < 0.001), physical and social functioning, and head and neck‐specific symptoms (swallowing, speech) at 12 months. Linear mixed models confirmed a favorable SIF trajectory over time (time‐by‐group interaction p < 0.001). Conclusion In patients with locally advanced OSCC undergoing NICT, SIF reconstruction offers comparable oncologic safety to FF while facilitating faster surgical recovery and yielding superior long‐term functional and quality of life outcomes.