Managing the invisible: Treatment approaches after pathological complete response (pCR) to neoadjuvant chemotherapy in oral cancer.

e18112 Background: Pathological complete response (pCR) following neoadjuvant chemotherapy (NACT) in locally advanced oral squamous cell carcinoma (LA-OSCC) is associated with improved overall survival (OS), locoregional control (LRC), and disease-free survival (DFS). However, there are no standardized guidelines for the management of patients achieving pCR, particularly regarding the role of adjuvant therapies. This study explores treatment strategies post-pCR and evaluates outcomes in oral cancer patients treated with NACT. Methods: Forty patients with LA-OSCC underwent three cycles of a three-drug NACT regimen (Cisplatin, 5-FU, and Docetaxel). Response assessments were performed using PET-CT at 12 weeks post-NACT. Patients with structural disease (fibrosis, scarring, or residual disease) underwent surgical resection. Cases with no residual tumor were classified as pCR. Treatment decisions for adjuvant therapy were individualized based on primary disease factors. Results: Patient cohort: 40 patients with LA-OSCC. Response assessment: PET-CT confirmed no residual tumor in pCR cases. pCR rates: Achieved in 27% of patients, consistent with existing literature for three-drug regimens. Adjuvant treatment: Patients with extranodal extension (ENE) received chemoradiotherapy (CTRT), while others were treated with radiotherapy (RT) alone to minimize toxicity. Failure rates: Local recurrence (10-20%) and distant metastasis (5-10%) were observed, emphasizing the need for tailored adjuvant therapy. Conclusions: Achieving pCR post-NACT is a favorable prognostic indicator in LA-OSCC. Adjuvant treatment decisions should be guided by disease-specific factors, such as ENE and other adverse features, to optimize outcomes while minimizing toxicity. Standardized evidence-based guidelines are urgently needed to streamline the management of pCR cases. Clinical implications: This study highlights the potential of individualized adjuvant therapy in improving outcomes for oral cancer patients achieving pCR. Future research should focus on integrating immunotherapy and identifying biomarkers predictive of pCR to refine treatment strategies.