Adjuvant Radiotherapy Significantly Increases Neck Control and Survival in Early Oral Cancer Patients with Solitary Nodal Involvement: A National Cancer Registry Database Analysis

SIMPLE SUMMARY: For early oral cancer with solitary nodal metastasis, the role of adjuvant radiotherapy on neck control and survival remains controversial. Based on our national cancer registry database, univariate and multivariable analysis showed that adjuvant radiotherapy significantly associated with better 5-year OS and DFS compared to patients who received surgery alone. Stratified analysis indicated the greatest survival advantage for 5-year OS and DFS in those with pT2 classification and non-tongue disease. Moreover, adjuvant radiotherapy significantly protected against neck recurrence. ABSTRACT: We assessed the role of adjuvant radiotherapy on neck control and survival in patients with early oral cancer with solitary nodal involvement. We identified pT1-2N1 oral cancer patients with or without adjuvant radiotherapy from the 2007–2015 Taiwan Cancer Registry database. The effect of adjuvant radiotherapy on 5-year neck control, overall survival (OS) and disease-free survival (DFS) were calculated using the Kaplan–Meier method, log-rank tests, and Cox regression analysis. Of 701 patients identified, 505 (72.0%) received adjuvant radiotherapy and 196 (28.0%) had surgery alone. Patients receiving adjuvant radiotherapy were more likely to be aged <65 years, pT2 stage, poorly graded and without comorbid conditions (all, p < 0.05). The 5-year OS and DFS differed significantly by receipt of adjuvant radiotherapy. Multivariable analysis showed adjuvant radiotherapy significantly associated with better 5-year OS (adjusted hazard ratio (aHR), 0.72; 95% confidence interval (CI), 0.54–0.97; p = 0.0288) and DFS (aHR, 0.64; 95% CI, 0.48–0.84; p = 0.0016). Stratified analysis indicated the greatest survival advantage for both 5-year OS and DFS in those with pT2 classification (p = 0.0097; 0.0009), and non-tongue disease (p = 0.0195; 0.0158). Moreover, adjuvant radiotherapy significantly protected against neck recurrence (aHR, 0.30; 95% CI, 0.18–0.51; p < 0.0001). Thus, adjuvant radiotherapy is associated with improved neck control and survival in these early oral cancer patients.