Postoperative Radiotherapy for Oral Squamous Cell Carcinoma After Neoadjuvant Therapy and Surgery

Inclusion Criteria: * Patients receiving neoadjuvant therapy and surgery for oral squamous cell carcinoma from January 2008 to December 2021 * Oral squamous cell carcinoma histology (including tongue, gingiva, cheek, floor of mouth, hard palate and posterior molar area) * Clinical stage III/IVA (T1-2/N1-2/M0 or T3-4/cN0-2/M0, AJCC 2018) for the primary lesion * Surgical resection samples that can be evaluated for pathological remission rate Exclusion Criteria: * Severe/active systemic disease * Previously radiotherapy or neck lymph node dissection for the head and neck region * Evidence of tumor recurrence or metastasis in physical examination or imaging (ultrasound, CT, MRI) before initiation adjuvant radiotherapy * Evidence of severe/unrelieved side effects of neoadjuvant therapy or severe postoperative complications before initiation adjuvant radiotherapy