Evaluating differentiation grade as a guide for decision-making in elective neck dissection for early-stage oral squamous cell carcinoma: a population-based cohort study.

Background: Early-stage oral squamous cell carcinoma (OSCC) frequently poses a risk of occult lymph node metastasis, complicating neck management decisions. Elective neck dissection (END) is a critical strategy for mitigating this risk, though its criteria for selection continue to be debated. This study evaluated whether tumor differentiation can guide END decisions in early-stage OSCC. Methods: Patients with stage I/II OSCC were identified from the Surveillance, Epidemiology, and End Results (SEER) database. Kaplan-Meier and Cox regression analyses assessed cancer-specific survival (CSS) and overall survival (OS), comparing END and no END groups across tumor differentiation grades. Stratified analyses further examined the influence of tumor site and size on survival. Results: Among 10,396 early-stage OSCC patients, END did not improve survival in well-differentiated tumors but significantly improved CSS and OS in moderately and poorly differentiated/undifferentiated tumors. Interaction analyses revealed that tumor site and size significantly modified END's survival benefit. Stratified analyses highlighted that END benefits patients with moderately or poorly differentiated/undifferentiated tumors, but provides limited benefit for well-differentiated, small tumors, or those located in the floor of mouth. Conclusions: Tumor differentiation is a critical determinant of END's survival benefit in early-stage OSCC. END should be considered for patients with moderately or poorly differentiated/undifferentiated tumors but may be unnecessary in well-differentiated cases.