Efficacy of postoperative neck irradiation for regional control in patients with pN0 oral tongue cancer: Propensity analysis

Background: The purpose of this study was to investigate whether adjuvant radiotherapy (RT) is efficacious for regional control and survival in patients with pN0 oral tongue cancer. Methods: Clinicopathological features of 166 patients with pN0 oral tongue cancer were compared between those who underwent adjuvant RT to the neck (neck RT-positive) and those who did not (neck RT-negative). Study endpoints were isolated regional recurrence and 3-year regional recurrence-free survival (RRFS). Propensity score matching was also performed. Results: Cox regression analysis did not reveal any significant predictor of isolated regional recurrence, including RT field. Three-year RRFS showed modest improvement in neck RT-positive group compared to neck RT-negative group before (92.2% vs 91.9%) and after propensity analysis (93.8% vs 83.3%), without statistical significance (log-rank P =.85 and.37, respectively). Conclusion: Despite more frequent unfavorable factors, the neck RT-positive group had a comparable oncologic outcome to the neck RT-negative group, suggesting that a marginal benefit in regional control might be expected from extending the RT field to the neck for pN0 oral tongue cancer.