Bilateral versus ipsilateral neck dissection in oral and oropharyngeal cancer with contralateral cN0 neck.

Objective: Contralateral elective neck dissection (cEND) in oral and oropharyngeal squamous cell cancer (OC/OPC) is still a matter of debate. The current study analyzed the outcome in OC/OPC patients with/without cEND.

Methods: OC/OPC patients (n = 471) were diagnosed with contralateral N0 after CT/MRI-scan combined with neck ultrasound. Clinico-pathological features were analyzed using Chi-square/Fisher exact/Student's t test. Survival rates were calculated using Kaplan-Meier and log-rank test. Prognostic variables were evaluated by Cox regression. Primary/secondary endpoints were overall/recurrence-free survival (OS/RFS).

Results: Pre-therapeutic imaging revealed a significantly over-staged N-status (p = 0.01), while occult contra-lateral N + was diagnosed in one patient only (0.4%). OC patients did not show differences in OS/RFS between the groups (ipsi- vs. bi-lateral). There was a strong tendency towards a better OS in OPC patients who underwent ipsi-lateral ND (p = 0.07). Cox-regression demonstrated that only tumor recurrence was associated with a fivefold increased risk of recurrence-associated death (p < 0.0001) that referred to a significant higher recurrence rate at primary tumor site (rT +) and increased distant metastatic outgrowth in OPC who underwent bi-lateral neck dissection (p = 0.03). While RFS of any cause (rT + /rN + /rM +) was significantly better in OPC with ipsi-lateral ND (p < 0.05), RFS of contralateral lymph node recurrence (rN2c) was comparable in both groups.

Conclusion: END of the contralateral cN0 neck is not correlated by an increased RFS or OS. Standard imaging techniques including CT/MRI scan and neck ultrasound warrant watchful waiting for neck dissection of the contralateral cN0 neck.