De-escalated surgery following neoadjuvant chemoimmunotherapy for locally advanced oral squamous cell carcinoma: A retrospective cohort study.

BACKGROUND: There remains considerable debate regarding whether the extent of surgery can be reduced in oral squamous cell carcinoma (OSCC) with significant tumor shrinkage after neoadjuvant chemoimmunotherapy. This study aims to report the feasibility and oncological safety of de-escalated surgery (DES) following neoadjuvant chemoimmunotherapy in locally advanced OSCC. MATERIALS AND METHODS: We collected clinical data of patients with locally advanced OSCC (T3-4 N0-3 M0) treated at our cancer center between November 2019 and July 2023 who received platinum-based doublet chemotherapy combined with a PD-1 inhibitor followed by DES. DES was defined as surgery performed according to the extent of residual tumor after neoadjuvant therapy. Tumor response, flap reconstruction/mandibulectomy exemption rates, event-free survival (EFS), and overall survival (OS) were assessed. RESULTS: A total of 111 patients were included, with tumors located in the tongue (73/111, 65.8 %), buccal-lip mucosa (15/111, 13.5 %), mandibular gingiva - floor of mouth (15/111, 13.5 %), and maxillary gingiva - hard palate (8/111, 7.2 %). The objective response rate (ORR) was 77.5 %, with a pathological complete response (pCR) rate of 40.5 %. Flap reconstruction was exempted in 80 (72.1 %) of patients. Among the 96 patients initially planned for mandibulectomy, 68 patients (70.8 %) were exempted from mandibulectomy. With a median follow-up of 27 months, the estimated 1-, 2-, and 3-year EFS rates were 90.1 %, 84.4 %, and 80.9 %, respectively. The estimated 1-, 2-, and 3-year OS rates were 97.3 %, 93.1 %, and 91.3 %, respectively. CONCLUSION: Opting for DES after neoadjuvant chemoimmunotherapy appears to be feasible, with satisfactory oncological safety in OSCC patients.