Patients with unilateral squamous cell carcinoma of the tongue and ipsilateral lymph node metastasis do not profit from bilateral neck dissection

The purpose of this study was to evaluate the necessity of elective bilateral neck dissection for treating strict unilateral squamous cell carcinoma (SCC) of the tongue. A cohort of 169 patients with unilateral non-midline crossing SCCs of the tongue treated by local resection and neck dissection was investigated. Study endpoints were nodal relapse and overall survival. The mean follow-up was 7.4 years. A total of 146 (88.1%) patients were treated by neck dissection. Lymph node metastases were diagnosed in 50 (34.2%) patients. Only two (1.1%) had contralateral lymph node metastases. Risk factors for developing a primary lymph node metastasis were size of tumor (T2/T3, p = 0.03; OR = 2.2), lymphangiosis (p = 0.003; OR = 4.7), and higher-grade differentiation (p = 0.051; OR = 2.43). Metachronous lymph node metastases were detected in 23 (13.6%) patients (19 ipsilateral, one contralateral and three bilateral). The main risk factor for developing a metachronous lymph node metastasis was the presence of a primary lymph node metastasis (p = 0.004; HR = 4.65). Patients with initial neck dissection came up with lower 5-year recurrence rates (13.6%) compared to patients without neck dissection (27.3%; p = 0.014). Bilateral neck dissection showed no advantage regarding nodal relapse free and overall survival (p = 0.606) compared to unilateral neck dissection irrespective of initial N or T stage. Patients with unilateral SCC of the tongue benefit from an ipsilateral neck dissection regarding nodal relapse. The value of elective bilateral neck dissection as standard treatment seems questionable even if positive lymph nodes were diagnosed ipsilateral at primary therapy.