Contralateral neck nodal outcomes and recurrence pattern of small well-lateralized oral cavity carcinoma—a single institution experience

Background: The administration of post-operative, contralateral neck nodal irradiation to patients with small, well-lateralized oral-cavity cancers is a controversial issue. We conducted a retrospective study to analyze the outcomes of these patients. Methods: We performed a single-institution, retrospective study of patients with pT1-2, pN0-2b [American Joint Committee on Cancer (AJCC) 6th/7th edition] well-lateralized oral-cavity cancer who underwent primary surgical intervention with or without adjuvant therapy from 2007–2017. Contralateral nodal failure-free survival (cNFFS), overall survival (OS), and event-free survival (EFS) were estimated by the Kaplan-Meier method. Outcomes of ipsilateral and contralateral neck irradiation were compared by the log-rank test. Results: One hundred and seventy-seven patients were evaluated with a median follow-up of 79.7 months. Adjuvant therapy was administered to 32.7% of patients. The 5-year cNFFS, OS, and EFS for all patients were 97.4%, 75.7%, and 67.9%, respectively. Of the 56 patients who received adjuvant radiotherapy (RT), no statistically significant differences between cNFFS, OS, and EFS were observed between ipsilateral and bilateral neck irradiation. Most (83.3%) local recurrence occurred prior to, or simultaneously with, contralateral neck recurrence. Conclusions: For small, well-lateralized oral-cavity cancers, the contralateral neck nodal recurrence rate was low. No significant impacts of contralateral neck irradiation were found. Local failure should be treated with caution because it may indicate higher contralateral neck failure.